Vaccine against S. suis infection

ABSTRACT

The present disclosure relates to immunogenic polypeptides, immunogenic compositions and vaccine compositions and use thereof for immunization of mammals susceptible to  Streptococcus suis  infection. The disclosure also relates to methods for preparing, formulating and administrating such compositions.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a § 371 national phase of International Application No. PCT/EP2016/066311, filed on Jul. 8, 2016, which claims the benefit of European Patent Application No. 15176063.4, filed on Jul. 9, 2015, which applications are incorporated by reference herein.

FIELD OF THE INVENTION

The present disclosure relates to immunogenic polypeptides, immunogenic compositions and vaccine compositions and use thereof for immunization of mammals susceptible to Streptococcus suis infection. The disclosure also relates to methods for preparing, formulating and administrating such compositions.

BACKGROUND

Streptococcus suis is a major pathogen causing bacterial disease in pigs and is responsible for large economic losses in the swine industry. S. suis causes a variety of diseases in pigs, including meningitis, arthritis, pericarditis, polyserositis, septicaemia, pneumonia and sudden death. Additionally, it is also emerging as a zoonotic agent of meningitis and streptococcal toxic shock-like syndrome and there is a high prevalence of S. suis human disease in southeast and east Asia. However, human cases have also been reported in several European countries, Australia as well North and South America. In western countries, S. suis infections are most often restricted to people who work in the swine industry, while in southeast and east Asia S. suis infections are a significant public health concern (Fittipaldi et al (2012), Future Microbiol. 7 (2); 259-279).

S. suis is a gram-positive facultative anaerobic coccus, originally defined as Lancefield groups R, S, R/S or T. Later, a new typing system based on the type-specific capsular polysaccharide antigens located in the cell wall was proposed. This led to a system comprising 35 serotypes (Rasmussen and Andresen (1998), Int. J. Syst. Bacteriol. 48, 1063-1065) of which serotypes 2, 1, 9, 7 and 1/2 are the most prevalent. Especially, serotype 2 has been reported as a zoonotic agent.

Control of S. suis in pig herd is of a large interest in the pig industry. Pigs may acquire S. suis via both vertical and horizontal transmission and colonized animals typically harbor the bacteria in their tonsils. While the adult pigs usually serve as asymptomatic carries, some carrier piglets will develop bacteremia, septicemia and/or meningitis due to dissemination of the bacteria from the tonsils and/or other mucosal surfaces. This usually occurs when the maternal antibodies decline in the piglets. To cause disease, the bacterial must breach the epithelial barriers, reach and survive in the bloodstream, invade different organs and cause exaggerated inflammation. The actual early mechanisms used by S. suis to colonize the host are poorly known, however several virulence factors have been proposed. The various S. suis virulence factors include; capsule, fibronectin/fibrinogen binding protein, serum opacity-like factor and modifications of the cell wall lipoteichoic acids and peptidoglycan (Fittipaldi supra). Furthermore, the virulence factors shared among various strains of the same serotype show a wide variation (Berthelot-Herault et al (2005) Can J Vet Res. July; 69(3):236-40; Quessy et al (1995) Infect Immun. May; 63(5):1975-9; Vecht et al (1992) Infect Immun. February; 60(2):550-6).

The development of vaccines have been focused on the above mentioned virulence factors. For example, vaccines compositions comprising a surface expressed protein, such as Sao and hp0245, are described in TW201412982, CN104248754 and CN102443053 and Li et al (2011) FEMS Micro Letters 316: 115-122. The protective effect of another surface localized protein (HP0197) is described in Zhang et al Vaccine (2009) 27: 5209-5213. A secreted protein (SsPepO) with a protective effect was described in Li et al (2011) Vaccine 29: 6514-6519. As of today, there is no well performing vaccine available against S. suis infection. In a recent study, the pan-surfome of S. suis was described identifying 113 surface expressed proteins (Gómez-Gascóna et al (2012), Journal of Proteomics October 22; 75(18):5654-66).

One commonly followed route to make a vaccine against a bacterial disease, is the production and testing of a whole cell vaccine preparation.

Known in the art is Porcilis® Strepsuis, an attenuated bacterial vaccine for immunization of healthy pigs against disease caused by S. suis serotype 2. Additionally, vaccines comprising Streptococcus mutants deficient in capsular expression and the htpsA-gene have been described in WO0005378 and CN103352015, respectively. It seems likely however (Kebede et al (1990), Vet. Microbiol. 22: 249-257), that protection obtained with whole cell preparations is serotype-specific. Additionally, there are other disadvantages of whole cell vaccines. For example, unwanted reactions at and around the site of injection are common and it is often required to administer a large amount of non-specific protein, compared to the amount of material actually responsible for the induction of protection. The limited availability of efficient vaccines is likely caused by the large number of existing serotypes, the variation in virulence among strains and the still scarce knowledge about the factors that contribute to virulence and protection. Recently, a protein encoded by IgM specific protease denoted Ide_(Ssuis) has been shown to elicit protective activity when immunized in pigs (Seele et al (2015) Vaccine, 33, 2207-2212), however large amounts of said protein are required for protective immunity, which leads to large costs associated with a vaccine based on said protein.

Lack of an effective vaccine against S. suis infections is a major problem in modern swine production. Thus, the provision of an effective and safe vaccine against S. suis infection is of large interest in the field.

SUMMARY OF THE INVENTION

It is an object of the present disclosure to provide an effective S. suis vaccine, which vaccine overcomes the disadvantages of the prior art, for example in terms of elicited protection and cost efficiency.

It is an object of the present disclosure to provide an immunogenic polypeptide for the use as a medicament, such as in prophylactic treatment of S. suis infections.

Also provided are immunogenic polypeptide fragments and fusion polypeptides per se.

Another object of the present disclosure is to provide related immunogenic compositions and vaccine composition as well as related treatment methods.

Yet another object of the present invention is to provide an immunogenic mixture with adjuvant properties.

These and other objects which are evident to the skilled person from the present disclosure are met by different aspects of the invention as claimed in the appended claims and as generally disclosed herein.

Briefly, the pan-surfome of S. suis has been described (Gómez-Gascóna supra). Gómez-Gascóna and co-workers obtained 39 S. suis strains obtained from infected pigs, corresponding to 19 of the most prevalent serotypes. They identified a set of 113 proteins, corresponding to both common and unique surface proteins in these strains, and listed them as potential antigens for vaccine development. The present inventors identified four of these as particularly useful in the context of a vaccine against S. suis infection.

The protein encoded by SSU0496 is an 1141 amino acid residues long IgM specific protease denoted IdeE (S. suis) or Ide_(Ssuis) (Seele et al (2013) Journal of Bacteriology, 195(5):930-940) and is herein denoted M2. The other three proteins (SSU0860, SSU1879 and SSU1355 denoted herein SP2, SP4 and SP7, respectively) show homology to the nucleotidase family of proteins. The importance of nucleotidases for virulence of bacteria has been shown for S. aureus (Thammavongsa et al 2009), S. sanguinis (Fan et al (2012) PLoS ONE 7(6): e38059), S. agalactiae (Firon et al (2014) The Journal of Biological Chemistry, 289(9):5479-5489) and S. suis (Liu et al (2014) The Journal of Infectious Diseases, Vol 210, Issue 1, p. 35-45). The published nucleotidase in S. suis has been denoted Ssads and corresponds to SP2. The two remaining selected polypeptides are putative genes: SP4 is a 813 amino acid long putative surface-anchored 2′,3′-cyclic-nucleotide 2′-phosphodiesterase; and SP7 is a 674 amino acid long putative surface-anchored 5′-nucleotidase.

Thus, present disclosure is based on the finding that the proteins M2, SP2, SP4 and SP7, which are expressed on the surface of S. suis, are useful in the context of prophylactic treatment of S. suis infection.

TABLE 1 Summary of selected antigens (immunogenic polypeptides) from S. suis P1/7. GenBank SEQ ID Accession Denotation Locus Protein NO: number SP2 SSU0860 Ssads 2 CAR45827 SP4 SSU1879 putative surface- 3 CAR47573 anchored 2′,3′- cyclic-nucleotide 2′- phosphodiesterase SP7 SSU1355 surface-anchored 4 CAR46815 5′-nucleotidase M2 SSU0496 IdeE (S. suis) 1 C5W022

Thus, in a first aspect of the present disclosure there is provided a an immunogenic polypeptide for use as a medicament, wherein said polypeptide comprises an amino acid sequence selected from the group consisting of SEQ ID NO:4 and fragments thereof; SEQ ID NO:3 and fragments thereof; SEQ ID NO:2 and fragments thereof; a fragment comprising SEQ ID NO:5, provided the fragment comprising SEQ ID NO:5 is less than 500 amino acids long; a fragment comprising SEQ ID NO:6, provided the fragment comprising SEQ ID NO:6 is less than 500 amino acids long; and amino acid sequences with at least 80%-identity to any one of said amino acid sequences, such as an amino acid sequence selected from the group consisting of SEQ ID NO:4 and fragments thereof; SEQ ID NO:3 and fragments thereof; SEQ ID NO:2 and fragments thereof; SEQ ID NO:5; SEQ ID NO:38, SEQ ID NO:6; and amino acid sequences with at least 80%-identity to any one of said amino acid sequences. The skilled person will appreciate that the immunogenic polypeptide may comprise the complete SP2, SP4, SP7 polypeptide or alternatively a fragment thereof, provided that said polypeptide comprises at least one immunogenic region. Also, the skilled person will appreciate that the immunogenic polypeptide may comprise M2N, M2N_(long) or M2C, which are fragments of M2, provided that it said immunogenic polypeptide comprising M2N, M2N_(long) or M2C does not encompass the full length M2 polypeptide. Thus in one embodiment, said fragment comprising SEQ ID NO:5 or SEQ ID NO:38 is less than 500 amino acids long, such as less than 450 amino acids long, such as less than 400 amino acids long. In one embodiment, said fragment comprising SEQ ID NO:6 is less than 500 amino acids long, such as less than 450 amino acids long, such as less than 400 amino acids long. In one embodiment, said fragment is at approximately 100-500 amino acids long, such as at approximately 200-500 amino acids long, such as at approximately 250-450 amino acids long.

As the skilled person will realize, the properties of a polypeptide, such as the immunogenicity of the polypeptides of the present disclosure, may be dependent on the tertiary structure of the polypeptide and the presence and accessibility of immunogenic regions within said polypeptide. It is therefore possible to make minor changes to the sequence of amino acids in a polypeptide without affecting the function thereof. Thus, the disclosure encompasses modified variants of the immunogenic polypeptide as described herein, which are such that the immunogenic characteristics are retained.

In this way, also encompassed by the present disclosure is an immunogenic polypeptide as defined herein comprising an amino acid sequence with at least 80%-identity to said SEQ ID NO:4 or fragment thereof; SEQ ID NO:3 or fragment thereof; SEQ ID NO:2 or fragment thereof; SEQ ID NO:5, SEQ ID NO:38 or SEQ ID NO:6. In some embodiments, the polypeptide may comprise a sequence which is at least 81%, such as at least 82% such as at least 83%, such as at least 84%, such as at least 85%, such as at least 86%, such as at least 87%, such as at least 88%, such as at least 89%, such as at least 90%, such as at least 91%, such as at least 92%, such as at least 93%, such as at least 93%, such as at least 95%, such as at least 96%, such as at least 97%, such as at least 98% or such as at least 99% identical to said SEQ ID NO:4, SEQ ID NO:3, SEQ ID NO:2, SEQ ID NO:5, SEQ ID NO:38 or SEQ ID NO:6. In some embodiments, said polypeptide may comprise a sequence which is at least 81%, such as at least 82% such as at least 83%, such as at least 84%, such as at least 85%, such as at least 86%, such as at least 87%, such as at least 88%, such as at least 89%, such as at least 90%, such as at least 91%, such as at least 92%, such as at least 93%, such as at least 93%, such as at least 95%, such as at least 96%, such as at least 97%, such as at least 98% or such as at least 99% identical to the corresponding fragment of SEQ ID NO:4, SEQ ID NO:3 or SEQ ID NO:2.

For example, it is possible that one or several amino acid residue belonging to a certain functional grouping of amino acid residues (e.g. hydrophobic, hydrophilic, polar etc.) could be exchanged for another amino acid residue from the same functional group. It is also possible, that one or several amino acid residues are exchanged for one or several amino acid residues that belong to a different functional group, provided that the resulting polypeptide retains its immunogenic properties.

The term “% identity”, as used throughout the specification, may for example be calculated as follows. The query sequence is aligned to the target sequence using the CLUSTAL W algorithm (Thompson et al, Nucleic Acids Research, 22: 4673-4680 (1994)). A comparison is made over the window corresponding to the shortest of the aligned sequences. The shortest of the aligned sequences may in some instances be the target sequence. In other instances, the query sequence may constitute the shortest of the aligned sequences. The amino acid residues at each position are compared, and the percentage of positions in the query sequence that have identical correspondences in the target sequence is reported as % identity.

To clarify, the text above relating to %-identity is equally relevant to the second, third and fourth aspects of the present disclosure and will for the sake of brevity not be repeated.

In one embodiment, there is provided immunogenic polypeptide for use in the prophylactic treatment of a S. suis infection, wherein said immunogenic polypeptide comprises an amino acid sequence selected from the group consisting of SEQ ID NO:4 and fragments thereof; SEQ ID NO:3 and fragments thereof; SEQ ID NO:2 and fragments thereof; a fragment comprising SEQ ID NO:5, provided the fragment comprising SEQ ID NO:5 is less than 500 amino acids long; a fragment comprising SEQ ID NO:6, provided the fragment comprising SEQ ID NO:6 is less than 500 amino acids long; and amino acid sequences with at least 80%-identity to any one of said amino acid sequences, such as an amino acid sequence selected from the group consisting of SEQ ID NO:4 and fragments thereof; SEQ ID NO:3 and fragments thereof; SEQ ID NO:2 and fragments thereof; SEQ ID NO:5; SEQ ID NO:38, SEQ ID NO:6; and amino acid sequences with at least 80%-identity to any one of said amino acid sequences.

In one embodiment of the present disclosure, there is provided an amino acid sequence for use as defined herein, which amino acid sequence is selected from the group consisting of SEQ ID NO:4 and fragments thereof, SEQ ID NO:3 and fragments thereof, SEQ ID NO:2 and fragments thereof; a fragment comprising SEQ ID NO:5, provided the fragment comprising SEQ ID NO:5 is less than 500 amino acids long; and amino acid sequences with at least 80%-identity to any one of said amino acid sequences, such as the group consisting of SEQ ID NO:4 and fragments thereof; SEQ ID NO:3 and fragments thereof; SEQ ID NO:2 and fragments thereof; SEQ ID NO:5; SEQ ID NO:38 and amino acid sequences with at least 80%-identity to any one of said amino acid sequences, such as the group consisting of SEQ ID NO:4 and fragments thereof; SEQ ID NO:3 and fragments thereof; SEQ ID NO:2 and fragments thereof; and amino acid sequences with at least 80%-identity to any one of said amino acid sequences.

In one embodiment, the prophylactic treatment is of a S. suis infection selected from the group of infections caused by any one of the 35 identified serotypes of S. suis. In another embodiment, said infection is selected from the group of infections caused by any one of serotypes 1, 2, 7, 9 and 1/2, such as the group of infections caused by any one of serotypes 1, 2 and 7, such as the group of infections caused by serotype 2 and 7. In one embodiment, said infection is caused by S. suis serotype 2 and in another embodiment said infection is cause by S. suis serotype 7. In one embodiment, there is provided an immunogenic polypeptide as described herein, for use in the prophylactic treatment of a S. suis infection, which immunogenic polypeptide fragment or fusion polypeptide is effective in the prophylactic treatment of infection caused by any one of at least 2, such as at least 3, such as at least 5, such as at least 7, such as at least 10 of the 35 identified serotypes.

As used herein, the term “prophylactic treatment” is a general term including anything between prevention of contracting the infection/disease and reduction of the severity of infection. The degree of prophylactic treatment can be measured in various ways, concerning e.g. S. suis infections in pigs the effect of the vaccine can be reduced clinical symptoms and reduced clinical disease. For example, reduced increase in temperature and reduced dissemination of bacteria from infected animals may be observed. Methods and procedures how to measure the efficacy of an immunizing composition after challenge are known to the person skilled in the art.

As used herein, the term “immunogenic” is used to refer to the properties of an immunogen, which is an entity capable of eliciting humoral and/or cell-mediated immune response. An immunogen first initiates an innate immune response, which then causes the activation of the adaptive immune response.

In contrast, the term “antigen” as used herein refers to an entity which has the potential to be immunogenic, however it is well established that not all antigens elicit immune responses. Thus, all immunogen molecules are also antigens, however the reverse is not true.

The skilled person is aware of the meaning of the term immunogenic, immunogen as well as antigenic and antigen.

As used herein, the term “fragment” of a molecule such as an immunogenic polypeptide fragment is meant to refer to a portion of the amino acid sequence of the full-length native polypeptide.

As used herein, the term “native polypeptide” is meant to refer to the form of a polypeptide which occurs in the nature and is as such not manipulated by molecular biology techniques. In the context of the present disclosure, native polypeptides include, but are not limited to, SSU0860, SSU1879, SSU1355 and SSU0496, corresponding to SEQ ID NO:2, 3, 4 and 1, respectively.

Thus, in one embodiment, there is provided an immunogenic polypeptide for use as described herein, wherein said polypeptide is selected from the group consisting of fragments of SEQ ID NO:4; fragments of SEQ ID NO:3; fragments of SEQ ID NO:2; a fragment comprising SEQ ID NO:5, provided the fragment comprising SEQ ID NO:5 is less than 500 amino acids long; a fragment comprising SEQ ID NO:6, provided the fragment comprising SEQ ID NO:6 is less than 500 amino acids long; and amino acid sequences with at least 80%-identity to any one of said fragments,

such as the group consisting of fragments of SEQ ID NO:4; fragments of SEQ ID NO:3; fragments of SEQ ID NO:2; a fragment comprising SEQ ID NO:5, provided the fragment comprising SEQ ID NO:5 is less than 500 amino acids long; and amino acid sequences with at least 80%-identity to any one of said fragments, such as the group consisting of fragments of SEQ ID NO:4; fragments of SEQ ID NO:3; fragments of SEQ ID NO:2; SEQ ID NO:5; SEQ ID NO:38; and amino acid sequences with at least 80%-identity to any one of said fragments, such as the group consisting of fragments of SEQ ID NO:4; fragments of SEQ ID NO:3; fragments of SEQ ID NO:2; and amino acid sequences with at least 80%-identity to said fragments.

The skilled person will appreciate that said fragments suitably contain at least one immunogenic region. In one particular embodiment, said fragment is at least 100 amino acids long, such at least 200 amino acids long, such as at least 250 amino acids long, such as at least 300 amino acids long. In one embodiment said fragment is less than 500 amino acids long, such as less than 450 amino acids long, such as less than 400 amino acids long. In one embodiment, said fragment is at approximately 100-500 amino acids long, such as at approximately 200-500 amino acids long, such as at approximately 250-450 amino acids long.

In one embodiment, the immunogenic polypeptide as described herein is an N-terminal fragment and in another embodiment, said immunogenic polypeptide is a C-terminal fragment. As used herein, the term “N-terminal fragment” refers to a fragment which comprises at least one amino acid located within 50 amino acid residues from the N-terminus of SEQ ID NO:1, SEQ ID NO:2, SEQ ID NO:3 and SEQ ID NO:4. As used herein, the term “C-terminal fragment” refers to a fragment which comprises at least one amino acid located within 250 amino acid residues from the C-terminus of SEQ ID NO:1. As used herein, the term “C-terminal fragment” refers to a fragment which comprises at least one amino acid located within 50 amino acid residues from the C-terminus of SEQ ID NO:2, SEQ ID NO:3 and SEQ ID NO:4. Thus, in one embodiment, said immunogenic polypeptide is an N-terminal fragment comprising at least one amino acid located within 50 amino acid residues from the N-terminus of SEQ ID NO:1. In one embodiment said immunogenic polypeptide is a C-terminal fragment comprising at least one amino acid located within 50 amino acid residues from the N-terminus of SEQ ID NO:2, SEQ ID NO:3 or SEQ ID NO:3. In one embodiment said immunogenic polypeptide is a C-terminal fragment comprising at least one amino acid located within 50 amino acid residues from the N-terminus of SEQ ID NO:2. In one embodiment said immunogenic polypeptide is a C-terminal fragment comprising at least one amino acid located within 50 amino acid residues from the N-terminus of SEQ ID NO:3 and in another embodiment, said immunogenic polypeptide is a C-terminal fragment comprising at least one amino acid located within 50 amino acid residues from the N-terminus of SEQ ID NO:4.

In one particular embodiment, there is provided an immunogenic polypeptide for use as described herein, wherein said polypeptide is a fragment selected from the group consisting of fragments comprising SEQ ID NO:7 or SEQ ID NO:8; fragments comprising SEQ ID NO:9 or SEQ ID NO:10; fragments comprising SEQ ID NO:11 or SEQ ID NO:12; a fragment comprising SEQ ID NO:5, provided the fragment comprising SEQ ID NO:5 is less than 500 amino acids long; a fragment comprising SEQ ID NO:6, provided the fragment comprising SEQ ID NO:6 is less than 500 amino acids long; and amino acid sequences with at least 80%-identity to any one of said fragments,

such as a fragment selected from the group consisting of fragments comprising SEQ ID NO:7 or SEQ ID NO:8; fragments comprising SEQ ID NO:9 or SEQ ID NO:10; fragments comprising SEQ ID NO:11 or SEQ ID NO:12; SEQ ID NO:5, SEQ ID NO:38 or SEQ ID NO:6; and amino acid sequences with at least 80%-identity to any one of said fragments, such as a fragment selected from the group consisting of fragments comprising SEQ ID NO:7 or SEQ ID NO:8; fragments comprising SEQ ID NO:9 or SEQ ID NO:10; fragments comprising SEQ ID NO:11 or SEQ ID NO:12; SEQ ID NO:5 or SEQ ID NO:38 (M2_(long)); and amino acid sequences with at least 80%-identity to any one of said fragments, such as a fragment selected from the group consisting of fragments comprising SEQ ID NO:7 or SEQ ID NO:8; fragments comprising SEQ ID NO:10; fragments comprising SEQ ID NO:12; SEQ ID NO:5; and amino acid sequences with at least 80%-identity to any one of said fragments.

In one embodiment, said fragment is selected from the group consisting of fragments comprising SEQ ID NO:7 or SEQ ID NO:8; fragments comprising SEQ ID NO:9 or SEQ ID NO:10; fragments comprising SEQ ID NO:11 or SEQ ID NO:12; a fragment comprising SEQ ID NO:5, provided the fragment comprising SEQ ID NO:5 is less than 500 amino acids long; and amino acid sequences with at least 80%-identity to any one of said fragments.

In one embodiment, said fragment is selected from the group consisting of fragments comprising SEQ ID NO:7 or SEQ ID NO:8; fragments comprising SEQ ID NO:10; fragments comprising SEQ ID NO:12; a fragment comprising SEQ ID NO:5, provided the fragment comprising SEQ ID NO:5 is less than 500 amino acids long; and amino acid sequences with at least 80%-identity to any one of said fragments.

In one embodiment, said fragment is selected from the group consisting of fragments comprising SEQ ID NO:8; fragments comprising SEQ ID NO:10; fragments comprising SEQ ID NO:12; a fragment comprising SEQ ID NO:5, provided the fragment comprising SEQ ID NO:5 is less than 500 amino acids long; and amino acid sequences with at least 80%-identity to any one of said fragments.

In one particular embodiment, said fragment is selected from the group consisting of fragments comprising SEQ ID NO:8; fragments comprising SEQ ID NO:10; fragments comprising SEQ ID NO:12; SEQ ID NO:5 or SEQ ID NO:38; and amino acid sequences with at least 80%-identity to any one of said fragments,

such as a fragment selected from the group consisting of fragments comprising SEQ ID NO:8; fragments comprising SEQ ID NO:10; fragments comprising SEQ ID NO:12; and SEQ ID NO:5; and amino acid sequences with at least 80%-identity to any one of said fragments, such as a fragment selected from the group consisting of fragments comprising SEQ ID NO:8; fragments comprising SEQ ID NO:10; fragments comprising SEQ ID NO:12; and amino acid sequences with at least 80%-identity to any one of said fragments.

In one particular embodiment, there is provided an immunogenic polypeptide for use as described herein, wherein said immunogenic polypeptide is a fragment selected from the group consisting of SEQ ID NO:7 or SEQ ID NO:8; SEQ ID NO:9 or SEQ ID NO:10; SEQ ID NO:11 or SEQ ID NO:12; and SEQ ID NO:5, SEQ ID NO:38 or SEQ ID NO:6; and amino acid sequences with at least 80%-identity to any one of said fragments, such as the group consisting of SEQ ID NO:7 or SEQ ID NO:8; SEQ ID NO:9 or SEQ ID NO:10; SEQ ID NO:11 or SEQ ID NO:12; SEQ ID NO:5 or SEQ ID NO:38; and amino acid sequences with at least 80%-identity to any one of said fragments, such as the group consisting SEQ ID NO:7 or SEQ ID NO:8; SEQ ID NO:10; SEQ ID NO:12; SEQ ID NO:5 or SEQ ID NO:38; and amino acid sequences with at least 80%-identity to any one of said fragments. In one embodiment, said fragment is selected from the group consisting of SEQ ID NO:8; SEQ ID NO:10; SEQ ID NO:12; SEQ ID NO:5; and amino acid sequences with at least 80%-identity to any one of said fragments. In another embodiment, said fragment is selected from the group consisting of SEQ ID NO:8; SEQ ID NO:10; SEQ ID NO:12; and amino acid sequences with at least 80%-identity to any one of said fragments.

In one embodiment, said fragment is SEQ ID NO:8 or a fragment with at least 80%-identity thereto. In another embodiment, said fragment is SEQ ID NO:10 or a fragment with at least 80%-identity thereto. In one embodiment, said fragment is SEQ ID NO:12 or a fragment with at least 80%-identity thereto. In one embodiment, said fragment is SEQ ID NO:5 or a fragment with at least 80%-identity thereto and in yet another embodiment said fragment is SEQ ID NO:38 or a fragment with at least 80%-identity thereto. In one embodiment, said fragment is SEQ ID NO:8; in another embodiment, said fragment is SEQ ID NO:10; in one embodiment, said fragment is SEQ ID NO:12; in one embodiment, said fragment is SEQ ID NO:5 and in yet another embodiment said fragment is SEQ ID NO:8.

It will be appreciated that polypeptides comprising minor changes as compared to the above amino acid sequences corresponding to SEQ ID NO:7, 8, 9, 10, 11, 12, 5, 38 and 6 without largely affecting immunogenicity are also within the scope of the present disclosure. Thus, in some embodiments, immunogenic polypeptide fragment as defined above may for example have a sequence which is at least 80% identical to the sequence of the corresponding fragment. In some embodiments, the polypeptide may comprise a sequence which is at least 81%, such as at least 82% such as at least 83%, such as at least 84%, such as at least 85%, such as at least 86%, such as at least 87%, such as at least 88%, such as at least 89%, such as at least 90%, such as at least 91%, such as at least 92%, such as at least 93%, such as at least 93%, such as at least 95%, such as at least 96%, such as at least 97%, such as at least 98% or such as at least 99 identical to said corresponding fragment.

The skilled person will understand that various modifications and/or additions can be made to an immunogenic polypeptide as defined herein, in order to tailor the polypeptide to a specific application without departing from the scope of the present disclosure. For example, an immunogenic polypeptide as defined herein may comprise additional amino acid residues for the purpose of improving production, purification and/or stabilization in vivo or in vitro of the polypeptide. Thus, an immunogenic polypeptide may comprise any suitable number of additional amino acid residues, for example at least one additional amino acid residue. Each additional amino acid residue may individually or collectively be added in order to, for example, improve production, purification, solubility and/or stabilization in vivo or in vitro. Such additional amino acid residues may also provide a “tag” for purification, such as a His-tag (also referred to herein as “—H” (such as for example a His₆-tag or a His₇-tag) or a “myc” (c-myc) tag or a “FLAG” tag for interaction with antibodies specific to the tag or immobilized metal affinity chromatography (IMAC) in the case of the His_-tag. The additional amino acid residues may also comprise a SL2-tag (SEQ ID NO:32) or LSL-tag (SEQ ID NO:33) as described herein.

Thus, in one embodiment, there is provided an immunogenic polypeptide for use as described herein, wherein said immunogenic polypeptide or fragment thereof further comprises additional amino acid residues at the N- and/or C-terminus of said fragment. Such an immunogenic polypeptide should be understood as a polypeptide having one or more additional amino acid residues at the very first and/or the very last position in the polypeptide chain, i.e. at the N- and/or C-terminus. For the sake of clarity, the presence of an additional amino acid residue at the N- and/or C-terminus of said immunogenic polypeptide does not preclude the presence of additional N- or C-terminal extensions, for example in the form a “tag” for purification as described above.

For example, in the case where the immunogenic polypeptide is selected from immunogenic polypeptides or fragments as defined herein, said additional amino acid residue at the N-terminus may be a methionine. Thus, in one embodiment, there is provided an immunogenic polypeptide as described herein, wherein said fragment comprises a methionine residue at the N-terminus. In one embodiment, said fragment comprises the amino acid residues MT, MTG or MTGS at the N-terminus. In one embodiment said fragment of comprises the amino acid residues LE at the C-terminus.

In one embodiment, there is provided an immunogenic polypeptide as described herein, wherein said additional amino acid residue(s) at the N-terminus and/or C-terminus or at the N-terminal and/or C-terminal improve production, purification and/or stabilization in vivo or in vitro of said immunogenic polypeptide.

In one embodiment, said additional amino acid residue(s) improve for purification of said immunogenic polypeptide. The additional amino acid residue(s) comprise a tag, such as a tag selected from the group consisting of a His_-tag, a “myc” (c-myc) tag, a SL2-tag (SEQ ID NO:32) or LSL-tag (SEQ ID NO:33) and a “FLAG” tag.

In one particular embodiment, said immunogenic polypeptide for use as described herein further comprises an amino acid sequence capable of binding to silica. In one embodiment, said amino acid sequence capable of binding to silica is selected from SEQ ID NO:32, SEQ ID NO:33 and amino acids sequences with at least 80%-identity to SEQ ID NO:32 or SEQ ID NO:33. In some embodiments, the amino acid sequence capable of binding to silica may exhibit at least 81%, such as at least 82% such as at least 83%, such as at least 84%, such as at least 85%, such as at least 86%, such as at least 87%, such as at least 88%, such as at least 89%, such as at least 90%, such as at least 91%, such as at least 92%, such as at least 93%, such as at least 93%, such as at least 95%, such as at least 96%, such as at least 97%, such as at least 98% or such as at least 99% sequence identity with SEQ ID NO:32 or SEQ ID NO:33.

In one embodiment, said amino acid sequence capable of binding to silica is SEQ ID NO:32. In another embodiment, said amino acid sequence capable of binding to silica is SEQ ID NO:33.

For the sake of clarity, the presence of additional amino acid residues at the N- and/or C-terminus of said immunogenic polypeptide does not preclude the presence of additional N- or C-terminal extensions, for example in the form a “tag” for purification as described above.

In one particular embodiment, said fragment may comprise the residues LE and the SL2-tag (SEQ ID NO:32) at the C-terminus and the amino acid residues MTGS at the N-terminus. In another embodiment, said fragment may comprise the amino acid residues MT, a His-tag and the amino acid residues GS at the N-terminus or the amino acid residues MTGS followed by the His-tag at the N-terminus.

In a second aspect of the present disclosure, there is provided a immunogenic polypeptide fragment, comprising an amino acid sequence selected from

-   -   i) an amino acid sequence selected the group consisting of SEQ         ID NO: 7, SEQ ID NO:8, SEQ ID NO:9, SEQ ID NO:10, SEQ ID NO:11         and SEQ ID NO:12, and,     -   ii) an amino acid sequence with at least 80%-identity to an         amino acid sequence defined in i).

In a third aspect of the present disclosure, there is provided a immunogenic polypeptide fragment, comprising an amino acid sequence selected from

-   -   iii) an amino acid sequence selected the group consisting of SEQ         ID NO:5, SEQ ID NO:38, SEQ ID NO:6, SEQ ID NO:7, SEQ ID NO:8,         SEQ ID NO:9, SEQ ID NO:10, SEQ ID NO:11 and SEQ ID NO:12, and,     -   iv) an amino acid sequence with at least 80%-identity to an         amino acid sequence defined in iii),         for use in the prophylactic treatment of a S. suis infection.

In one embodiment, said fragment is at approximately 100-500 amino acids long, such as at approximately 200-500 amino acids long, such as at approximately 250-450 amino acids long.

The skilled person will appreciate that the following disclosure is equally relevant in the context of the second and third aspects described herein. Thus, the skilled person will appreciate that any of said fragments may be immunogenic, provided it comprises at least one immunogenic region. Again, polypeptides comprising minor changes as compared to the above amino acid sequences corresponding to SEQ ID NO:7, 8, 9, 10, 11, 12, 5, 38 and 6 without largely affecting immunogenicity are also within the scope of the present disclosure. Thus, in some embodiments, immunogenic polypeptide fragment as defined above may for example have a sequence which is at least 80% identical to the sequence defined by i) or iii). In some embodiments, the polypeptide may comprise a sequence which is at least 81%, such as at least 82% such as at least 83%, such as at least 84%, such as at least 85%, such as at least 86%, such as at least 87%, such as at least 88%, such as at least 89%, such as at least 90%, such as at least 91%, such as at least 92%, such as at least 93%, such as at least 93%, such as at least 95%, such as at least 96%, such as at least 97%, such as at least 98% or such as at least 99% identical to said to the sequence defined by i) or iii).

In one embodiment there is provided an immunogenic polypeptide fragment, wherein the sequence iii) is selected from the group consisting of SEQ ID NO:5, SEQ ID NO:38, SEQ ID NO:8, SEQ ID NO:10 and SEQ ID NO:12, such as the group consisting of SEQ ID NO:5, SEQ ID NO:8, SEQ ID NO:10 and SEQ ID NO:12. In one embodiment, there is provided an immunogenic polypeptide fragment, wherein the sequence i) or iii) is selected from the group consisting of SEQ ID NO:8, SEQ ID NO:10 and SEQ ID NO:12, such as the group consisting of SEQ ID NO:10 and SEQ ID NO:12, such as the group consisting of SEQ ID NO:8 and SEQ ID NO:12, such as the group consisting of SEQ ID NO:8 and SEQ ID NO:10. In one embodiment, there is provided an immunogenic polypeptide fragment, wherein the sequence i) or iii) is SEQ ID NO:8, SEQ ID NO:10 or SEQ ID NO:12. In one embodiment, there is provided an immunogenic polypeptide fragment, wherein the sequence iii) is SEQ ID NO:5.

The skilled person will appreciate that fragments of any one of SP2, SP4 and SP7 (for example SP2N, SP2C, SP4N, SP4C, SP7N or SP7C) or fragment comprising M2N or M2C (for example M2N, M2N_(long) or M2C), provided said fragments are less than 500 amino acids long, may be arranged in the form of a fusion polypeptide and that such fusion polypeptides may exhibit equally good or better immunogenic properties compared to said fragments individually. For example, such fusion polypeptides may comprise two or more immunogenic regions. As used herein, the term “fusion polypeptide” refers to a polypeptide comprising a least two units which are derived from different native polypeptides or proteins.

Thus, in a first embodiment of the fourth aspect disclosed herein, there is provided a fusion polypeptide comprising

a) a first immunogenic polypeptide unit, and

b) a second immunogenic polypeptide unit,

wherein at least one of said first and second immunogenic polypeptide units is selected from the group consisting of fragments of SEQ ID NO:4, fragments of SEQ ID NO:3, fragments of SEQ ID NO:2, a fragment comprising SEQ ID NO:5, provided the fragment comprising SEQ ID NO:5 is less than 500 amino acids long; a fragment comprising SEQ ID NO:6, provided the fragment comprising SEQ ID NO:6 is less than 500 amino acids long; and amino acid sequences with at least 80%-identity to any one of said fragments, such as the group consisting of fragments of SEQ ID NO:4, fragments of SEQ ID NO:3, fragments of SEQ ID NO:2, a fragment comprising SEQ ID NO:5, provided the fragment comprising SEQ ID NO:5 is less than 500 amino acids long, and amino acid sequences with at least 80%-identity to any one of said fragments. In one embodiment, said first and second immunogenic polypeptide units are selected from the group consisting of fragments comprising the group consisting of fragments of SEQ ID NO:4; fragments of SEQ ID NO:3; fragments of SEQ ID NO:2; SEQ ID NO:5; SEQ ID NO:38; SEQ ID NO:6, and amino acid sequences with at least 80%-identity to any one of said fragments, provided that said first and said second immunogenic polypeptide units are from different native proteins. In one embodiment, at least one of said first and second immunogenic polypeptide units is a immunogenic polypeptide fragment selected from the group consisting of fragments of SEQ ID NO:4; fragments of SEQ ID NO:3; fragments of SEQ ID NO:2; SEQ ID NO:5; and SEQ ID NO:38, and amino acid sequences with at least 80%-identity to any one of said fragments. In one embodiment, at least one of said first and second immunogenic polypeptide units is immunogenic polypeptide fragment selected from the group consisting of fragments of SEQ ID NO:4; fragments of SEQ ID NO:3 and fragments of SEQ ID NO:2; and amino acid sequences with at least 80%-identity to any one of said fragments.

In one embodiment of the this aspect, there is provided a fusion polypeptide comprising

c) a first immunogenic polypeptide unit, and

d) a second immunogenic polypeptide unit,

wherein said first and second immunogenic polypeptide units are selected from the group consisting of fragments of SEQ ID NO:4, fragments of SEQ ID NO:3, fragments of SEQ ID NO:2, a fragment comprising SEQ ID NO:5, provided the fragment comprising SEQ ID NO:5 is less than 500 amino acids long; a fragment comprising SEQ ID NO:6, provided the fragment comprising SEQ ID NO:6 is less than 500 amino acids long; and amino acid sequences with at least 80%-identity to any one of said fragments, such as the group consisting of fragments of SEQ ID NO:4, fragments of SEQ ID NO:3, fragments of SEQ ID NO:2, a fragment comprising SEQ ID NO:5, provided the fragment comprising SEQ ID NO:5 is less than 500 amino acids long, and amino acid sequences with at least 80%-identity to any one of said fragments. In one embodiment, said first and second immunogenic polypeptide units are selected from the group consisting of fragments comprising the group consisting of fragments of SEQ ID NO:4; fragments of SEQ ID NO:3; fragments of SEQ ID NO:2; SEQ ID NO:5; SEQ ID NO:38; SEQ ID NO:6, and amino acid sequences with at least 80%-identity to any one of said fragments, provided that said first and said second immunogenic polypeptide units are from different native proteins. In one embodiment, said first and second immunogenic polypeptide units are immunogenic polypeptide fragments selected from the group consisting of fragments of SEQ ID NO:4; fragments of SEQ ID NO:3; fragments of SEQ ID NO:2; SEQ ID NO:5; and SEQ ID NO:38, and amino acid sequences with at least 80%-identity to any one of said fragments. In one embodiment, said first and second immunogenic polypeptide units are immunogenic polypeptide fragments selected from the group consisting of fragments of SEQ ID NO:4; fragments of SEQ ID NO:3 and fragments of SEQ ID NO:2; and amino acid sequences with at least 80%-identity to any one of said fragments.

In one particular embodiment, there is provided a fusion polypeptide as defined herein, further comprising a third immunogenic polypeptide unit, which unit is selected from the units defined above, provided that said third immunogenic polypeptide unit is from a different native proteins than said first and second immunogenic polypeptide units. To clarify, any two of said first, second and third polypeptide units may not be from the same native protein, or be derived from said native proteins. As used herein, the term “derived from a native protein” encompasses polypeptides exhibiting more than 80 identity with native proteins or a corresponding fragment thereof. Non-limiting examples of fusion polypeptides comprising three units are SEQ ID NO:107 and 108. Also SEQ ID NO:109 and 110 are examples of fusion polypeptides comprising three units.

For the sake of clarity, the designation of first, second and third immunogenic polypeptide unit as used throughout the present disclosure is made for clarity reasons to distinguish between them, and is not intended to refer to the actual order of the immunogenic polypeptide unit in the polypeptide chain of the fusion polypeptide. Thus, for example, said first immunogenic polypeptide unit may appear N-terminally or C-terminally in a polypeptide chain, with respect to said second and third immunogenic polypeptide units, respectively.

In one particular embodiment, said immunogenic polypeptide units are, independently of each other, at least 100 amino acids long, such as at least 200 amino acids long, such as at least 250 amino acids long, such as at least 300 amino acids long. In one embodiment said immunogenic peptide units are, independently of each other, less than 500 amino acids long, such as less than 450 amino acids long, such as less than 400 amino acids long. In one embodiment, each of the first, second immunogenic and optionally third polypeptide unit are, independently of each other, approximately 100-500 amino acids long, such as approximately 200-500 amino acids long, such as approximately 250-450 amino acids long.

In one embodiment, said first, second and optional third immunogenic polypeptide units are selected from the group consisting of fragments comprising SEQ ID NO:7 or SEQ ID NO:8; fragments comprising SEQ ID NO:9 or SEQ ID NO:10; fragments comprising SEQ ID NO:11 or SEQ ID NO:12; a fragment comprising SEQ ID NO:5, provided the fragment comprising SEQ ID NO:5 is less than 500 amino acids long and; a fragment comprising SEQ ID NO:6, provided the fragment comprising SEQ ID NO:6 is less than 500 amino acids long; and amino acid sequences with at least 80%-identity to any one of said fragments,

such as the group consisting of fragments comprising SEQ ID NO:7 or SEQ ID NO:8; fragments comprising SEQ ID NO:9 or SEQ ID NO:10; fragments comprising SEQ ID NO:11 or SEQ ID NO:12; a fragment comprising SEQ ID NO:5, provided the fragment comprising SEQ ID NO:5 is less than 500 amino acids long; and amino acid sequences with at least 80%-identity to any one of said fragments, such as the group consisting of fragments comprising SEQ ID NO:7 or SEQ ID NO:8; fragments comprising SEQ ID NO:10; fragments comprising SEQ ID NO:12; a fragment comprising SEQ ID NO:5, provided the fragment comprising SEQ ID NO:5 is less than 500 amino acids long; and amino acid sequences with at least 80%-identity to any one of said fragments, such as the group consisting of fragments comprising SEQ ID NO:8; fragments comprising SEQ ID NO:10; fragments comprising SEQ ID NO:12; a fragment comprising SEQ ID NO:5, provided the fragment comprising SEQ ID NO:5 is less than 500 amino acids long; and amino acid sequences with at least 80%-identity to any one of said fragments, such as the group consisting of fragments comprising SEQ ID NO:8; fragments comprising SEQ ID NO:10; fragments comprising SEQ ID NO:12; and amino acid sequences with at least 80%-identity to any one of said fragments.

In one embodiment, said first, second and optional third immunogenic polypeptide units are selected from the group consisting of fragments SEQ ID NO:5, SEQ ID NO:38, SEQ ID NO:6, SEQ ID NO:7, SEQ ID NO:8, SEQ ID NO:9, SEQ ID NO:10, SEQ ID NO:11 and SEQ ID NO:12, and amino acid sequences with at least 80%-identity to any one of said fragments,

such as the group consisting of fragments SEQ ID NO:5, SEQ ID NO:38, SEQ ID NO:7, SEQ ID NO:8, SEQ ID NO:9, SEQ ID NO:10, SEQ ID NO:11 and SEQ ID NO:12, and amino acid sequences with at least 80%-identity to any one of said fragments,

such as the group consisting of fragments SEQ ID NO:5, SEQ ID NO:38, SEQ ID NO:7, SEQ ID NO:8, SEQ ID NO:10, and SEQ ID NO:12, and amino acid sequences with at least 80%-identity to any one of said fragments,

such as the group consisting of fragments SEQ ID NO:5, SEQ ID NO:38, SEQ ID NO:8, SEQ ID NO:10, and SEQ ID NO:12, and amino acid sequences with at least 80%-identity to any one of said fragments, such as the group consisting of fragments SEQ ID NO:8, SEQ ID NO:10, and SEQ ID NO:12, and amino acid sequences with at least 80%-identity to any one of said fragments.

In one embodiment, there is provided a fusion polypeptide as described herein selected from the group consisting of fusion polypeptides comprising SEQ ID NO:9 and SEQ ID NO:7; fusion polypeptides comprising SEQ ID NO:10 and SEQ ID NO:7; fusion polypeptides comprising SEQ ID NO:11 and SEQ ID NO:7; fusion polypeptides comprising SEQ ID NO:12 and SEQ ID NO:7; fusion polypeptides comprising SEQ ID NO:5 and SEQ ID NO:7; fusion polypeptides comprising SEQ ID NO:38 and SEQ ID NO:7; fusion polypeptides comprising SEQ ID NO:6 and SEQ ID NO:7; fusion polypeptides comprising SEQ ID NO:9 and SEQ ID NO:8; fusion polypeptides comprising SEQ ID NO:10 and SEQ ID NO:8; fusion polypeptides comprising SEQ ID NO:11 and SEQ ID NO:8; fusion polypeptides comprising SEQ ID NO:12 and SEQ ID NO:8; fusion polypeptides comprising SEQ ID NO:5 and SEQ ID NO:8; SEQ ID NO:38 and SEQ ID NO:8; SEQ ID NO:6 and SEQ ID NO:8; fusion polypeptides comprising SEQ ID NO:11 and SEQ ID NO:9; fusion polypeptides comprising SEQ ID NO:12 and SEQ ID NO:9; fusion polypeptides comprising SEQ ID NO:5 and SEQ ID NO:9; fusion polypeptides comprising SEQ ID NO:38 and SEQ ID NO:9; fusion polypeptides comprising SEQ ID NO:6 and SEQ ID NO:9; fusion polypeptides comprising SEQ ID NO:11 and SEQ ID NO:10; fusion polypeptides comprising SEQ ID NO:12 and SEQ ID NO:10; fusion polypeptides comprising SEQ ID NO:5 and SEQ ID NO:10; fusion polypeptides comprising SEQ ID NO:38 and SEQ ID NO:10; fusion polypeptides comprising SEQ ID NO:6 and SEQ ID NO:10; fusion polypeptides comprising SEQ ID NO:5 and SEQ ID NO:11; fusion polypeptides comprising SEQ ID NO:38 and SEQ ID NO:11; fusion polypeptides comprising SEQ ID NO:6 and SEQ ID NO:11; fusion polypeptides comprising SEQ ID NO:5 and SEQ ID NO:12; SEQ ID NO:38 and SEQ ID NO:12; and fusion polypeptides comprising SEQ ID NO:6 and SEQ ID NO:12,

such as the group consisting of fusion polypeptides comprising SEQ ID NO:9 and SEQ ID NO:7; fusion polypeptides comprising SEQ ID NO:10 and SEQ ID NO:7; fusion polypeptides comprising SEQ ID NO:11 and SEQ ID NO:7; fusion polypeptides comprising SEQ ID NO:12 and SEQ ID NO:7; fusion polypeptides comprising SEQ ID NO:5 and SEQ ID NO:7; fusion polypeptides comprising SEQ ID NO:6 and SEQ ID NO:7; fusion polypeptides comprising SEQ ID NO:9 and SEQ ID NO:8; fusion polypeptides comprising SEQ ID NO:10 and SEQ ID NO:8; fusion polypeptides comprising SEQ ID NO:11 and SEQ ID NO:8; fusion polypeptides comprising SEQ ID NO:12 and SEQ ID NO:8; fusion polypeptides comprising SEQ ID NO:5 and SEQ ID NO:8; fusion polypeptides comprising SEQ ID NO:6 and SEQ ID NO:8; fusion polypeptides comprising SEQ ID NO:11 and SEQ ID NO:9; fusion polypeptides comprising SEQ ID NO:12 and SEQ ID NO:9; fusion polypeptides comprising SEQ ID NO:5 and SEQ ID NO:9; fusion polypeptides comprising SEQ ID NO:6 and SEQ ID NO:9; fusion polypeptides comprising SEQ ID NO:11 and SEQ ID NO:10; fusion polypeptides comprising SEQ ID NO:12 and SEQ ID NO:10; fusion polypeptides comprising SEQ ID NO:5 and SEQ ID NO:10; fusion polypeptides comprising SEQ ID NO:6 and SEQ ID NO:10; fusion polypeptides comprising SEQ ID NO:5 and SEQ ID NO:11; fusion polypeptides comprising SEQ ID NO:6 and SEQ ID NO:11; fusion polypeptides comprising SEQ ID NO:5 and fusion polypeptides comprising SEQ ID NO:12; and SEQ ID NO:6 and SEQ ID NO:12, such as the group consisting of fusion polypeptides comprising SEQ ID NO:10 and SEQ ID NO:8; fusion polypeptides comprising SEQ ID NO:5 and SEQ ID NO:12; fusion polypeptides comprising SEQ ID NO:5 and SEQ ID NO:10; fusion polypeptides comprising SEQ ID NO:8 and SEQ ID NO:12; SEQ ID NO:8 and fusion polypeptides comprising SEQ ID NO:5 or SEQ ID NO:38; and fusion polypeptides comprising SEQ ID NO:12 and SEQ ID NO:10, such as the group consisting of fusion polypeptides comprising SEQ ID NO:10 and SEQ ID NO:8; fusion polypeptides comprising SEQ ID NO:8 and SEQ ID NO:5; fusion polypeptides comprising SEQ ID NO:8 and SEQ ID NO:38; and fusion polypeptides comprising SEQ ID NO:12 and SEQ ID NO:10, such as the group consisting of fusion polypeptides comprising SEQ ID NO:8 and SEQ ID NO:5; fusion polypeptides comprising SEQ ID NO:8 and SEQ ID NO:38; and fusion polypeptides comprising SEQ ID NO:12 and SEQ ID NO:10.

In one embodiment, said fusion polypeptide comprises SEQ ID NO:8 and SEQ ID NO:5. In one embodiment, said fusion polypeptide comprises SEQ ID NO:8 and SEQ ID NO:38. In another embodiment, said fusion polypeptide comprises SEQ ID NO:12 and SEQ ID NO:10.

In one particular embodiment of the fusion polypeptide disclosed herein, said fusion polypeptide comprises an amino acid sequence selected from the group consisting of SEQ ID NO:92, SEQ ID NO:93, SEQ ID NO:94, SEQ ID NO:95, SEQ ID NO:96, SEQ ID NO:34, SEQ ID NO:35 and any of said fusion polypeptides wherein at least one of said units exhibits at least 80%-identity to any one of SEQ ID NO:8, SEQ ID NO:10, SEQ ID NO:12 or SEQ ID NO:5. In one embodiment, said fusion polypeptide comprises a amino acid sequence selected from the group consisting of SEQ ID NO:34; SEQ ID NO:35; SEQ ID NO:92 and any of said fusion polypeptides wherein at least one of said units exhibits at least 80%-identity to any one of SEQ ID NO:8, SEQ ID NO:10, SEQ ID NO:12 and SEQ ID NO:5, such as the group consisting SEQ ID NO:34; SEQ ID NO:35, and any of said fusion polypeptides wherein at least one of said units exhibits at least 80%-identity to any one of SEQ ID NO:8, SEQ ID NO:10, SEQ ID NO:12 and SEQ ID NO:5.

As mentioned above, within the scope of the present disclosure there are fusion polypeptides comprising three or four immunogenic polypeptide fragments or units as described herein. Thus, in one embodiment said fusion polypeptide comprises three or four of the immunogenic polypeptide fragments as disclosed herein. In one particular embodiment, said fusion polypeptide comprises SEQ ID NO:5, SEQ ID NO:8 and SEQ ID NO:12 or an immunogenic polypeptide fragments which exhibits at least 80%-identity to any one of SEQ ID NO:5, SEQ ID NO:8 and SEQ ID NO:12. In one particular embodiment, said fusion polypeptide comprises SEQ ID NO:5, SEQ ID NO:8 and SEQ ID NO:12. In one embodiment, said fusion polypeptide comprises SEQ ID NO:5, SEQ ID NO:10 and SEQ ID NO:12 or an immunogenic polypeptide fragments which exhibits at least 80%-identity to any one of SEQ ID NO:5, SEQ ID NO:10 and SEQ ID NO:12. In one embodiment, said fusion polypeptide comprises SEQ ID NO:5, SEQ ID NO:10 and SEQ ID NO:12. In one embodiment, said fusion polypeptide comprises SEQ ID NO:8, SEQ ID NO:10 and SEQ ID NO:12 or an immunogenic polypeptide fragments which exhibits at least 80%-identity to any one of SEQ ID NO:8, SEQ ID NO:10 and SEQ ID NO:12. In one embodiment, said fusion polypeptide comprises SEQ ID NO:8, SEQ ID NO:10 and SEQ ID NO:12. To clarify, the present disclosure encompasses fusion polypeptides, wherein one, two, three or four units exhibit at least 80%-identity to the aforementioned units. Thus, in one embodiment, said fusion polypeptide comprises an immunogenic polypeptide unit with at least 80%-identity with SEQ ID NO:8, an immunogenic polypeptide unit with at least 80%-identity with SEQ ID NO:10 and an immunogenic polypeptide unit with at least 80%-identity with SEQ ID NO:12, preferably comprising an immunogenic polypeptide unit with 100%-identity with SEQ ID NO:8, an immunogenic polypeptide unit with 100%-identity with SEQ ID NO:10 and an immunogenic polypeptide unit with 100%-identity with SEQ ID NO:12. To clarify, in the context of the fusion polypeptide, the term unit refers to a immunogenic polypeptide fragment. In other words, the

fusion polypeptide may comprises an immunogenic polypeptide fragment with at least 80%-identity with SEQ ID NO:8, an immunogenic polypeptide fragment with at least 80%-identity with SEQ ID NO:10 and an immunogenic polypeptide fragment with at least 80%-identity with SEQ ID NO:12, preferably comprising an immunogenic polypeptide fragment with 100%-identity with SEQ ID NO:8, an immunogenic polypeptide fragment with 100%-identity with SEQ ID NO:10 and an immunogenic polypeptide fragment with 100%-identity with SEQ ID NO:12.

For example, said fusion polypeptide may comprise SEQ ID NO:8, SEQ ID NO:10 and a polypeptide which exhibits at least 80% identity to SEQ ID NO:12; or said fusion polypeptide may comprise SEQ ID NO:8, a polypeptide which exhibits at least 80% identity to SEQ ID NO:10 and a polypeptide which exhibits at least 80% identity to SEQ ID NO:12; or said fusion polypeptide may comprise polypeptide which exhibits at least 80 identity to SEQ ID NO:8, a polypeptide which exhibits at least 80% identity to SEQ ID NO:10 and a polypeptide which exhibits at least 80% identity to SEQ ID NO:12. Thus, encompassed herein are fusion polypeptides wherein one, two or three polypeptide units exhibit at least 80% identity to SEQ ID NO:8, 10 and/or 12. In particular embodiment, said fusion polypeptide comprises SEQ ID NO:35 and SEQ ID NO:8. In one embodiment, the SEQ ID NO:8 is located N-terminally in respect of SEQ ID NO:35. In another embodiment, the SEQ ID NO:8 is located C-terminally in respect of SEQ ID NO:35. In one embodiment, said fusion comprises SEQ ID NO:107 or SEQ ID NO:108 or a polypeptide which exhibits at least 80%-identity thereto. In one embodiment, said fusion comprises SEQ ID NO:109 or SEQ ID NO:110 or a polypeptide which exhibits at least 80%-identity thereto.

In one embodiment, said fusion polypeptide comprises SEQ ID NO:109 or SEQ ID NO:110. In one embodiment, there is provided a fusion polypeptide selected from the group consisting of SEQ ID NO:107, 108, 109, 110 and amino acid sequences which exhibit at least 80%-identity to any one of SEQ ID NO:107, 108, 109 and 110. In one embodiment, the fusion polypeptide is selected from the group consisting of SEQ ID NO:107, 109 and amino acid sequences which exhibit at least 80%-identity to any one of SEQ ID NO:107 and 109. In one embodiment, the fusion polypeptide is selected from the group consisting of SEQ ID NO:108, 110 and amino acid sequences which exhibit at least 80%-identity to any one of SEQ ID NO:108 and 110.

The skilled person will appreciate that the above statements regarding sequence identity and %-identity are equally applicable in the present context and are not repeated for the sake of brevity.

As the skilled person understands, the construction of a fusion polypeptide often involves the use of linkers between functional moieties to be fused. The skilled person is aware of different kinds of linkers with different properties, such as flexible amino acid linkers, rigid amino acid linkers and cleavable amino acid linkers. Linkers have been used to for example increase stability or improve folding of fusion polypeptides, to increase expression, improve biological activity, enable targeting and alter pharmacokinetics of fusion polypeptides.

Thus, in one embodiment of the first aspect, there is provided a fusion polypeptide as defined herein, wherein said linker is selected from the group consisting of flexible amino acid linkers, rigid amino acid linkers and cleavable amino acid linkers. In one embodiment of a fusion polypeptide as defined herein, said linker is arranged between the first immunogenic polypeptide fragment and the second immunogenic polypeptide fragment. The skilled person will appreciate that the presence of a linker arranged between the first immunogenic polypeptide fragment and the immunogenic polypeptide fragment unit does not exclude the presence of additional linkers.

Flexible linkers are often used in the art when the joined domains require a certain degree of movement or interaction, and may be particularly useful in some embodiments of the fusion polypeptide as described herein. Such linkers are generally composed of small, non-polar (for example G) or polar (for example S or T) amino acids. Some flexible linkers primarily consist of stretches of G and S residues, for example (GGGGS)_(p) and (SSSSG)_(p). Adjusting the copy number “p” allows for optimization of the linker in order to achieve appropriate separation between the functional moieties or to maintain necessary inter-moiety interaction. Apart from G and S linkers, other flexible linkers are known in the art, such as G and S linkers containing additional amino acid residues, such as T, A, K and E, to maintain flexibility, as well as polar amino acid residues to improve solubility.

Additional non-limiting examples of linkers include GGGGSLVPRGSGGGGS (SEQ ID NO:113), (GS)₃ (SEQ ID NO:14), (GS)₄ (SEQ ID NO:115), (GS)₈ (SEQ ID NO:116), GGSGGHMGSGG (SEQ ID NO:117), GGSGGSGGSGG (SEQ ID NO:118), GGSGG (SEQ ID NO:119), GGSGGGGG (SEQ ID NO:120), GGGSEGGGSEGGGSEGGG (SEQ ID NO:121), AAGAATAA (SEQ ID NO:122), GGGGG (SEQ ID NO:123), GGSSG (SEQ ID NO:124), GSGGGTGGGSG (SEQ ID NO:125), GSGGGTGGGSG (SEQ ID NO:126), GT, GSGSGSGSGGSG (SEQ ID NO:127), GSGGSGGSGGSGGS (SEQ ID NO:128) and GSGGSGSGGSGGSG (SEQ ID NO:129). The skilled person is aware of other suitable linkers.

In one embodiment, said linker is a flexible linker comprising glycine (G), serine (S) and/or threonine (T) residues. In one embodiment, said linker has a general formula selected from (G_(n)S_(m))_(p) and (S_(m)G_(n))_(p), wherein, independently, n=1-7, m=0-7, n+m 8 and p=1-7. In one embodiment, n=1-5. In one embodiment, m=0-5. In one embodiment, p=1-5. In a more specific embodiment, n=4, m=1 and p=1-4. In one embodiment, said linker is selected from the group consisting of 5₄G, (5₄G)₃ and (5₄G)₄. In one embodiment, said linker is selected from the group consisting of G₄S and (G₄S)₃. In one particular embodiment, said linker is G₄S and in another embodiment said linker is (G₄S)₃. In one embodiment, said linker has the general formula (G_(e)T_(f))_(q), wherein, independently, e=1-3, f=1-3, and q=1-4. In one embodiment, q=1-3. In a more specific embodiment, e=1, f=1 and q=1-3. In one embodiment, said linker is selected from the group consisting of GT, (GT)₂ and (GT)₃. In one embodiment, said linker is GT. In one embodiment, the linker is EF.

It will be appreciated that the immunogenic polypeptide fragment as described herein and the fusion polypeptide as described herein, may further comprise additional amino acid residues at the N- and/or C-terminus and that the description of possible additional amino acid residues in the context of the first aspect of the present disclosure is equally relevant for the second, third and fourth aspects. For the sake of brevity these will not be repeated here or will only be briefly mentioned.

Thus, in one embodiment there is provided an immunogenic polypeptide fragment or a fusion polypeptide as described herein, wherein said fragment or fusion polypeptide further comprises additional amino acid residues at the N- and/or C-terminus. In one embodiment, said immunogenic polypeptide fragment or fusion polypeptide, comprises a methionine residue at the N-terminus. In one embodiment, said immunogenic polypeptide fragment or fusion polypeptide, comprises the amino acids residues MT, MTG or MTGS at the N-terminus. In one embodiment, said additional amino acid residue(s) comprise a tag, such as a tag selected from the group consisting of a His-tag, a “myc” (c-myc) tag, a SL-tag (SEQ ID NO:32), a LSL-tag (SEQ ID NO:33) and a “FLAG” tag. In another embodiment, said immunogenic polypeptide fragment or fusion polypeptide, comprises an amino acid sequence capable of binding to silica. In one embodiment, said immunogenic polypeptide fragment or fusion polypeptide, comprises an amino acid sequence selected from SEQ ID NO:32, SEQ ID NO:33 and amino acids sequences with at least 80%-identity to SEQ ID NO:32 or 33, such as wherein said amino acid sequence is SEQ ID NO:32 or 33. In one embodiment, said amino acid sequence capable of binding to silica SEQ ID NO:32. In another embodiment, said amino acid sequence capable of binding to silica SEQ ID NO:33.

The skilled person will appreciate that the immunogenic polypeptide fragment or fusion polypeptide described herein may be useful as a medicament, for example as a medicament for use prophylactic treatment of a S. suis infection, such as in vaccination. Thus in one embodiment, there is provided an immunogenic polypeptide fragment or fusion polypeptide as defined herein, for use as a medicament. In another embodiment, there is said immunogenic polypeptide fragment or said fusion polypeptide may be used in the prophylactic treatment of a S. suis infection. In one embodiment, said prophylactic treatment is of an S. suis infection selected from the group of infections caused by any one of the 35 identified serotypes of S. suis. In another embodiment, said infection is selected from the group of infections caused by any one of serotypes 1, 2, 7, 9 and 1/2, such as the group of infections caused by any one of serotypes 1, 2 and 7, such as the group of infections caused by serotype 2 and 7. In one embodiment, said infection is cause by S. suis serotype 2 and in another embodiment said infection is cause by S. suis serotype 7. In one embodiment, there is provided an immunogenic polypeptide fragment or fusion polypeptide as described herein, for use in the prophylactic treatment of a S. suis infection, which immunogenic polypeptide fragment or fusion polypeptide is effective in the prophylactic treatment of infection caused by any one of at least 2, such as at least 3, such as at least 5, such as at least 7, such as at least 10 of the 35 identified serotypes.

In a fifth aspect of the present disclosure, there is provided a polynucleotide encoding an immunogenic polypeptide for use as defined herein, an immunogenic polypeptide fragment as described herein or a fusion polypeptide as described herein. Also encompassed by this disclosure is an expression vector comprising the polynucleotide and a host cell comprising the expression vector. Encompassed is also a method of producing an immunogenic polypeptide, an immunogenic polypeptide fragment or a fusion polypeptide, comprising culturing said host cell under conditions permissive of expression of said polypeptide from its expression vector, and isolating the polypeptide. Alternatively, the immunogenic polypeptide, immunogenic polypeptide fragment or fusion polypeptide of the present disclosure may alternatively be produced by non-biological peptide synthesis using amino acids and/or amino acid derivatives having protected reactive side-chains, the non-biological peptide synthesis comprising

-   -   step-wise coupling of the amino acids and/or the amino acid         derivatives to form a polypeptide according to the first, second         or third aspect having protected reactive side-chains,     -   removal of the protecting groups from the reactive side-chains         of the polypeptide, and     -   folding of the polypeptide in aqueous solution.

The skilled person will appreciate that any one of the above mentioned immunogenic polypeptides, immunogenic polypeptide fragments and fusion polypeptides may be useful in an immunogenic composition. For the sake of clarity, the term “immunogenic composition” herein refers to compositions other than bacteria, such as native bacteria or attenuated bacteria. Thus, in a sixth aspect of the present disclosure, there is provided an immunogenic composition comprising at least one immunogenic polypeptide selected from the group consisting of in immunogenic polypeptide as according to the first aspect disclosed herein, an immunogenic polypeptide fragment according to the second or third aspect as disclosed herein or an fusion polypeptide according to the fourth aspect as disclosed herein.

In one embodiment, there is provided an immunogenic composition as disclosed herein, comprising one, two, three or four of said immunogenic polypeptides or immunogenic polypeptide fragments, such as two, three or four of said immunogenic polypeptides or immunogenic polypeptide fragments, such as three or four of said immunogenic polypeptides or immunogenic polypeptide fragments, such as four of said immunogenic polypeptides or immunogenic polypeptide fragments. In one embodiment, said at least one immunogenic polypeptide fragment is provided in fusion with a different at least one different immunogenic polypeptide fragment to form a fusion polypeptide as described herein.

The skilled person will appreciate that it may be beneficial for the immunogenic composition to comprise several distinct immunogenic fragments, which are capable of eliciting an immune response. Said distinct immunogenic fragment may be present on one polypeptide chain or on several polypeptide chains. Thus is one embodiment, there is provided an immunogenic composition, comprising at least one of the immunogenic polypeptides as defined herein, at least one immunogenic polypeptide fragment as defined herein or at least one fusion polypeptide as defined herein. In one embodiment, said immunogenic composition comprises two, three or four immunogenic polypeptides as defined herein. In one particular embodiment, there is provided an the immunogenic composition wherein said at least one fragment as defined herein is provided in fusion with a different at least one different immunogenic polypeptide fragment as defined herein to form a fusion polypeptide as defined herein. The provision of two or more immunogenic fragments in the form of a fusion polypeptide may be beneficial for technical production purposes as well as for cost saving purposes.

In one embodiment, there is provided an immunogenic composition as described herein, wherein said composition comprises a fusion polypeptide as defined herein and optionally one or two immunogenic polypeptide fragments as defined herein not in the form of a fusion polypeptide. In one embodiment, said composition comprises a fusion polypeptide comprising two immunogenic polypeptide fragments as defined herein and optionally one immunogenic polypeptide fragment as defined herein not in the form of a fusion polypeptide.

In one embodiment, there is provided an immunogenic composition, wherein said composition comprises a fusion polypeptide comprising three or four immunogenic polypeptide fragments as defined herein. In one embodiment, said composition comprises a fusion polypeptide comprising three immunogenic polypeptide fragments as defined herein and optionally one immunogenic polypeptide fragments as defined herein not in the form of a fusion polypeptide. In one embodiment, there is provided an immunogenic composition comprising one or two fusion polypeptides. Thus, said immunogenic composition may for example comprise one fusion polypeptide; one fusion polypeptide and one individual polypeptides; one fusion polypeptide and two individual polypeptides; one fusion polypeptide and three or more individual polypeptides; two fusion polypeptides or more fusion polypeptides.

In one particular embodiment, there is provided an immunogenic composition selected from the group consisting of immunogenic compositions comprising

a fusion polypeptide comprising SEQ ID NO:9 and SEQ ID NO:7 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO: 5, 6, 11 and 12 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:10 and SEQ ID NO:7 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO: 5, 6, 11 and 12 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:11 and SEQ ID NO:7 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO: 5, 6, 9 and 10 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:12 and SEQ ID NO:7 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO: 5, 6, 9 and 10 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:5 and SEQ ID NO:7 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO: 9, 10, 11 and 12 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:6 and SEQ ID NO:7 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO: 9, 10, 11 and 12 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:9 and SEQ ID NO:8 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO: 5, 6, 11 and 12 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:10 and SEQ ID NO:8 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO: 5, 6, 11 and 12 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:11 and SEQ ID NO:8 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO: 5, 6, 9 and 10 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:12 and SEQ ID NO:8 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO: 5, 6, 9 and 10 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:5 and SEQ ID NO:8 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO: 9, 10, 11 and 12 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:6 and SEQ ID NO:8 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO: 9, 10, 11 and 12 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:11 and SEQ ID NO:9 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO: 5, 6, 7 and 8 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:12 and SEQ ID NO:9 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO: 5, 6, 7 and 8 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:5 and SEQ ID NO:9 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO: 7, 8, 11 and 12 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:6 and SEQ ID NO:9 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO: 7, 8, 11 and 12 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:11 and SEQ ID NO:10 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO: 5, 6, 7 and 8 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:12 and SEQ ID NO:10 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO: 5, 6, 7 and 8 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:5 and SEQ ID NO:10 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO: 7, 8, 11 and 12 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:6 and SEQ ID NO:10 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO: 7, 8, 11 and 12 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:5 and SEQ ID NO:11 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO: 7, 8, 9 and 10 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:6 and SEQ ID NO:11 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO: 7, 8, 9 and 10 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:5 and SEQ ID NO:12 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO: 7, 8, 9 and 10 not in the form of a fusion polypeptide; and

a fusion polypeptide comprising SEQ ID NO:6 and SEQ ID NO:12 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO: 7, 8, 9 and 10 not in the form of a fusion polypeptide; such as the group consisting of immunogenic compositions comprising

a fusion polypeptide comprising SEQ ID NO:10 and SEQ ID NO:8 and at least one polypeptide comprising an e amino acid sequence selected from SEQ ID NO: 5, 6, 11 and 12 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:5 and SEQ ID NO:12 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO: 7, 8, 9 and 10 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:5 and SEQ ID NO:10 and at least one polypeptide comprising an e amino acid sequence selected from SEQ ID NO: 7, 8, 11 and 12 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:8 and SEQ ID NO:12 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO: 5, 6, 9 and 10 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:8 and SEQ ID NO:5 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO: 9, 10, 11 and 12 not in the form of a fusion polypeptide; and

a fusion polypeptide comprising SEQ ID NO:12 and SEQ ID NO:10 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO: 5, 6, 8 and 9 not in the form of a fusion polypeptide; such as the group consisting of immunogenic compositions comprising

a fusion polypeptide comprising SEQ ID NO:10 and SEQ ID NO:8 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO: 5, 6, 11 and 12 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:8 and SEQ ID NO:5 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO: 9, 10, 11 and 12 not in the form of a fusion polypeptide; and

a fusion polypeptide comprising SEQ ID NO:12 and SEQ ID NO:10 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO: 5, 6, 7 and 8 not in the form of a fusion polypeptide; such as the group consisting of immunogenic compositions comprising

a fusion polypeptide comprising SEQ ID NO:8 and SEQ ID NO:5 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO: 9, 10, 11 and 12 not in the form of a fusion polypeptide; or

a fusion polypeptide comprising SEQ ID NO:12 and SEQ ID NO:10 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO: 5, 6, 8 and 9 not in the form of a fusion polypeptide.

In particular embodiments, the immunogenic composition as disclosed herein is selected from the one of the groups above, provided that the immunogenic composition does not comprise SEQ ID NO:6 not in the form of a fusion polypeptide. For the sake of brevity, said embodiments will not be repeated here. For example, the immunogenic composition may comprise a fusion polypeptide comprising SEQ ID NO:10 and SEQ ID NO:8 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:5, 11 and 12 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:8 and SEQ ID NO:5 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:9, 10, 11 and 12 not in the form of a fusion polypeptide; or

a fusion polypeptide comprising SEQ ID NO:12 and SEQ ID NO:10 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:5, 7 and 8 not in the form of a fusion polypeptide.

In another particular embodiment, there is provided an immunogenic composition selected from the group of immunogenic compositions consisting of immunogenic compositions comprising

a fusion polypeptide comprising SEQ ID NO:9 and SEQ ID NO:7 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:11 and 12 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:10 and SEQ ID NO:7 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:11 and 12 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:11 and SEQ ID NO:7 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:9 and 10 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:12 and SEQ ID NO:7 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:9 and 10 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:5 and SEQ ID NO:7 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:9, 10, 11 and 12 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:6 and SEQ ID NO:7 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:9, 10, 11 and 12 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:9 and SEQ ID NO:8 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:11 and 12 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:10 and SEQ ID NO:8 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:11 and 12 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:11 and SEQ ID NO:8 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:9 and 10 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:12 and SEQ ID NO:8 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:9 and 10 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:5 and SEQ ID NO:8 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:9, 10, 11 and 12 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:6 and SEQ ID NO:8 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:9, 10, 11 and 12 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:11 and SEQ ID NO:9 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:7 and 8 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:12 and SEQ ID NO:9 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:7 and 8 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:5 and SEQ ID NO:9 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:7, 8, 11 and 12 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:6 and SEQ ID NO:9 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:7, 8, 11 and 12 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:11 and SEQ ID NO:10 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:7 and 8 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:12 and SEQ ID NO:10 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:7 and 8 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:5 and SEQ ID NO:10 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:7, 8, 11 and 12 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:6 and SEQ ID NO:10 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:7, 8, 11 and 12 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:5 and SEQ ID NO:11 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:7, 8, 9 and 10 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:6 and SEQ ID NO:11 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:7, 8, 9 and 10 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:5 and SEQ ID NO:12 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:7, 8, 9 and 10 not in the form of a fusion polypeptide; and

a fusion polypeptide comprising SEQ ID NO:6 and SEQ ID NO:12 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:7, 8, 9 and 10 not in the form of a fusion polypeptide; such as the group consisting of immunogenic compositions comprising

a fusion polypeptide comprising SEQ ID NO:10 and SEQ ID NO:8 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:11 and 12 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:5 and SEQ ID NO:12 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:7, 8, 9 and 10 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:5 and SEQ ID NO:10 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:7, 8, 11 and 12 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:8 and SEQ ID NO:12 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:9 and 10 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:8 and SEQ ID NO:5 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:9, 10, 11 and 12 not in the form of a fusion polypeptide; and

a fusion polypeptide comprising SEQ ID NO:12 and SEQ ID NO:10 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:8 and 9 not in the form of a fusion polypeptide; such as the group consisting of immunogenic compositions comprising

a fusion polypeptide comprising SEQ ID NO:10 and SEQ ID NO:8 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:11 and 12 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:8 and SEQ ID NO:5 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:9, 10, 11 and 12 not in the form of a fusion polypeptide; and

a fusion polypeptide comprising SEQ ID NO:12 and SEQ ID NO:10 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:7 and 8 not in the form of a fusion polypeptide; such as the group consisting of immunogenic compositions comprising

a fusion polypeptide comprising SEQ ID NO:8 and SEQ ID NO:5 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:9, 10, 11 and 12 not in the form of a fusion polypeptide; and

a fusion polypeptide comprising SEQ ID NO:12 and SEQ ID NO:10 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:8 and 9 not in the form of a fusion polypeptide.

In one particular embodiment, said immunogenic composition is selected from the group consisting of immunogenic compositions comprising

a fusion polypeptide comprising SEQ ID NO:10 and SEQ ID NO:8 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:5 and 12 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:5 and SEQ ID NO:12 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:8 and 10 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:5 and SEQ ID NO:10 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:8 and 12 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:8 and SEQ ID NO:12 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:5 and 10 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:8 and SEQ ID NO:5 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:10 and 12 not in the form of a fusion polypeptide; and

a fusion polypeptide comprising SEQ ID NO:12 and SEQ ID NO:10 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:5 and 8 not in the form of a fusion polypeptide; such as the group consisting of immunogenic compositions comprising

a fusion polypeptide comprising SEQ ID NO:10 and SEQ ID NO:8 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:5 and 12 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:8 and SEQ ID NO:5 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:10 and 12 not in the form of a fusion polypeptide; and

a fusion polypeptide comprising SEQ ID NO:12 and SEQ ID NO:10 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:5 and 8 not in the form of a fusion polypeptide; such as the group consisting of immunogenic compositions comprising

a fusion polypeptide comprising SEQ ID NO:8 and SEQ ID NO:5 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:10 and 12 not in the form of a fusion polypeptide; and

a fusion polypeptide comprising SEQ ID NO:12 and SEQ ID NO:10 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:5 and 8 not in the form of a fusion polypeptide.

In one particular embodiment, said immunogenic composition is selected from the group consisting of immunogenic compositions comprising

a fusion polypeptide comprising SEQ ID NO:10 and SEQ ID NO:8 and a polypeptide comprising the amino acid sequence SEQ ID NO:12 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:5 and SEQ ID NO:12 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:8 and 10 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:5 and SEQ ID NO:10 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:8 and 12 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:8 and SEQ ID NO:12 and a polypeptide comprising the amino acid sequence SEQ ID NO:10 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:8 and SEQ ID NO:5 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:10 and 12 not in the form of a fusion polypeptide; and

a fusion polypeptide comprising SEQ ID NO:12 and SEQ ID NO:10 and a polypeptide comprising the amino acid sequence SEQ ID NO:8 not in the form of a fusion polypeptide; such as the group consisting of immunogenic compositions comprising

a fusion polypeptide comprising SEQ ID NO:10 and SEQ ID NO:8 and a polypeptide comprising the amino acid sequence SEQ ID NO:12 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:8 and SEQ ID NO:5 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:10 and 12 not in the form of a fusion polypeptide; and

a fusion polypeptide comprising SEQ ID NO:12 and SEQ ID NO:10 and a polypeptide comprising the amino acid sequence SEQ ID NO:8 not in the form of a fusion polypeptide; such as the group consisting of immunogenic compositions comprising

a fusion polypeptide comprising SEQ ID NO:8 and SEQ ID NO:5 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:10 and 12 not in the form of a fusion polypeptide; and

a fusion polypeptide comprising SEQ ID NO:12 and SEQ ID NO:10 and a polypeptide comprising the amino acid sequence SEQ ID NO:8 not in the form of a fusion polypeptide.

In one particular embodiment, said immunogenic composition is selected from the group consisting of immunogenic compositions comprising

a fusion polypeptide comprising SEQ ID NO:10 and SEQ ID NO:8 and a polypeptide comprising the amino acid sequence SEQ ID NO:12 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:10 and SEQ ID NO:12 and a polypeptide comprising the amino acid sequence SEQ ID NO:8 not in the form of a fusion polypeptide; and

a fusion polypeptide comprising SEQ ID NO:8 and SEQ ID NO:12 and a polypeptide comprising the amino acid sequence SEQ ID NO:10 not in the form of a fusion polypeptide.

In one embodiment as defined herein, the immunogenic composition a comprises two amino acid sequences not in the form of a fusion polypeptide, provided that said two amino acid sequences are from different native proteins.

In one particular embodiment of the immunogenic composition as defined herein, said fusion polypeptide is selected from the group consisting of fusion polypeptides comprising SEQ ID NO:92, fusion polypeptides comprising SEQ ID NO:93, fusion polypeptides comprising SEQ ID NO:94, fusion polypeptides comprising SEQ ID NO:95, fusion polypeptides comprising SEQ ID NO:96, fusion polypeptides comprising SEQ ID NO:34, fusion polypeptides comprising SEQ ID NO:35, and any of fusion polypeptides wherein one or both units exhibit at least 80%-identity to any one of SEQ ID NO:8, SEQ ID NO:10, SEQ ID NO:12 or SEQ ID NO:5,

such as the group consisting of fusion polypeptides comprising SEQ ID NO:92, fusion polypeptides comprising SEQ ID NO:34 and fusion polypeptides comprising SEQ ID NO:35 and any of fusion polypeptides wherein one or both units exhibit at least 80%-identity to any one of SEQ ID NO:8, SEQ ID NO:10, SEQ ID NO:12 or SEQ ID NO:5, such as the group consisting of fusion polypeptides comprising SEQ ID NO:34 and fusion polypeptides comprising SEQ ID NO:35, and any of said fusion polypeptides wherein one or both units exhibit at least 80%-identity to any one of SEQ ID NO:8, SEQ ID NO:10, SEQ ID NO:12 or SEQ ID NO:5.

In one embodiment of the immunogenic composition defined herein, there is provided an immunogenic composition selected from the group of consisting of immunogenic compositions comprising

a fusion polypeptide comprising SEQ ID NO:92 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:5 and 12 not in the form of a fusion polypeptide,

a fusion polypeptide comprising SEQ ID NO:93 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:8 and 10 not in the form of a fusion polypeptide,

a fusion polypeptide comprising SEQ ID NO:94 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:8 and 10 not in the form of a fusion polypeptide,

a fusion polypeptide comprising SEQ ID NO:95 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:8 and 12 not in the form of a fusion polypeptide,

a fusion polypeptide comprising SEQ ID NO:96 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:5 and 10 not in the form of a fusion polypeptide,

a fusion polypeptide comprising SEQ ID NO:34 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:10 and 12 not in the form of a fusion polypeptide, and

a fusion polypeptide comprising SEQ ID NO:35 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:5 and 8 not in the form of a fusion polypeptide; and

any of fusion polypeptides wherein one or both units exhibit at least 80%-identity to any one of SEQ ID NO:8, SEQ ID NO:10, SEQ ID NO:12 or SEQ ID NO:5,

such as the group consisting of immunogenic compositions comprising

a fusion polypeptide comprising SEQ ID NO:92 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:5 and 12 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:34 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:10 and 12 not in the form of a fusion polypeptide;

a fusion polypeptide comprising SEQ ID NO:35 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:5 and 8 not in the form of a fusion polypeptide; and

any of fusion polypeptides wherein one or both units exhibit at least 80%-identity to any one of SEQ ID NO:8, SEQ ID NO:10, SEQ ID NO:12 or SEQ ID NO:5:

such as the group consisting of immunogenic compositions comprising

a fusion polypeptide comprising SEQ ID NO:34 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:10 and 12 not in the form of a fusion polypeptide; and

a fusion polypeptide comprising SEQ ID NO:35 and at least one polypeptide comprising an amino acid sequence selected from SEQ ID NO:5 and 8 not in the form of a fusion polypeptide; and

any of said fusion polypeptides wherein one or both units exhibit at least 80%-identity to any one of SEQ ID NO:8, SEQ ID NO:10, SEQ ID NO:12 or SEQ ID NO:5.

In one embodiment, said immunogenic compositions comprises two fusion polypeptides selected from the group of fusion polypeptides consisting of fusion polypeptides comprising SEQ ID NO:92, fusion polypeptides comprising SEQ ID NO:93, fusion polypeptides comprising SEQ ID NO:94, fusion polypeptides comprising SEQ ID NO:95, fusion polypeptides comprising SEQ ID NO:96, fusion polypeptides comprising SEQ ID NO:34, fusion polypeptides comprising SEQ ID NO:35, and any of fusion polypeptides wherein one or both units exhibit at least 80%-identity to any one of SEQ ID NO:8, SEQ ID NO:10, SEQ ID NO:12 or SEQ ID NO:5,

such as the group of fusion polypeptides consisting of fusion polypeptides comprising SEQ ID NO:92, fusion polypeptides comprising SEQ ID NO:34, fusion polypeptides comprising SEQ ID NO:35 and any of fusion polypeptides wherein one or both units exhibit at least 80%-identity to any one of SEQ ID NO:8, SEQ ID NO:10, SEQ ID NO:12 or SEQ ID NO:5, such as the group of fusion polypeptides consisting of fusion polypeptides comprising SEQ ID NO:34 and fusion polypeptides comprising SEQ ID NO:35, and any of said fusion polypeptides wherein one or both units exhibit at least %-identity 80 to any one of SEQ ID NO:8, SEQ ID NO:10, SEQ ID NO:12 or SEQ ID NO:5. In one embodiment, said immunogenic composition comprises fusion polypeptide SEQ ID NO:34 and fusion polypeptide SEQ ID NO:35.

In one particular embodiment the immunogenic composition as disclosed herein comprises a fusion polypeptide selected from the group consisting of fusion polypeptides comprising

SEQ ID NO:5, SEQ ID NO:8 and SEQ ID NO:12;

SEQ ID NO:38, SEQ ID NO:8 and SEQ ID NO:12;

SEQ ID NO:5, SEQ ID NO:10 and SEQ ID NO:12;

SEQ ID NO:38, SEQ ID NO:10 and SEQ ID NO:12;

SEQ ID NO:8, SEQ ID NO:10 and SEQ ID NO:12; and

fusion polypeptides wherein at least one of the first, second or third polypeptide units exhibits at least 80%-identity to any one of SEQ ID NO:5; SEQ ID NO:8, SEQ ID NO:38, SEQ ID NO:10 and SEQ ID NO:12. In one embodiment, said fusion polypeptide comprises SEQ ID NO:8, SEQ ID NO:10 and SEQ ID NO:12 or a fusion polypeptide wherein at least one of the first, second or third polypeptide units exhibits at least 80%-identity to any one of SEQ ID NO:8, SEQ ID NO:10 and SEQ ID NO:12. In one embodiment, said fusion polypeptide comprises SEQ ID NO:8, SEQ ID NO:10 and SEQ ID NO:12.

In particular embodiment, the immunogenic composition as disclosed herein comprises a fusion polypeptide comprising SEQ ID NO:35 and SEQ ID NO:8. In one embodiment, the SEQ ID NO:8 is located N-terminally in respect of SEQ ID NO:35. In another embodiment, the SEQ ID NO:8 is located C-terminally in respect of SEQ ID NO:35. In one embodiment, said fusion polypeptide comprises SEQ ID NO:107 or SEQ ID NO:108 or a sequence which exhibits at least 80% identity to SEQ ID NO:107 or SEQ ID NO:108. In one embodiment, said fusion polypeptide comprises SEQ ID NO:107 or SEQ ID NO:108. Optionally, said fusion polypeptide may comprise a tag, as described herein. Said fusion polypeptide may thus be SEQ ID NO:109 or SEQ ID NO:110 or a sequence which exhibits at least 80% identity to SEQ ID NO:109 or SEQ ID NO:110. In one embodiment, said fusion polypeptide comprises SEQ ID NO:109 or SEQ ID NO:110. In one embodiment, there is provided an immunogenic composition comprising a fusion polypeptide selected from the group consisting of SEQ ID NO:107, 108, 109, 110 and amino acid sequences which exhibit at least 80%-identity to any one of SEQ ID NO:107, 108, 109 and 110. In one embodiment, the immunogenic composition comprises a fusion polypeptide selected from the group consisting of SEQ ID NO:107, 109 and amino acid sequences which exhibit at least 80%-identity to any one of SEQ ID NO:107 and 109. In one embodiment, the immunogenic composition comprises a fusion polypeptide selected from the group consisting of SEQ ID NO:108, 110 and amino acid sequences which exhibit at least 80%-identity to any one of SEQ ID NO:108 and 110.

It will be appreciated that the immunogenic polypeptide as described herein, immunogenic polypeptide fragment as described herein and the fusion polypeptide as described herein, may further comprise additional amino acid residues at the N- and/or C-terminus and that the description of possible additional amino acid residues in the context of the first aspect of the present disclosure is equally relevant for immunogenic polypeptides, immunogenic polypeptide fragments and fusion polypeptides making up the immunogenic composition of the fifth aspect. For the sake of brevity these will not be repeated here.

It will be appreciated that the polypeptide components of the immunogenic composition as described herein may be isolated or purified from S. suis. Alternatively, they may be produced according to recombinant techniques. Thus, in one embodiment, there is provided an immunogenic composition, comprising one or several polypeptide and/or fusion polypeptide which are recombinantly produced. The skilled person will appreciate that for the purpose of recombinant production, it may be beneficial in terms of cost to produce shorter polypeptides, such as fragments of full length proteins or fragments derived from full length proteins, as compared to polypeptides which correspond to said full length proteins. Additionally, it will be appreciated that it may also be beneficial to produce one polypeptide chain instead of two or more polypeptide chains, in order to reduce production costs. For example, it may be beneficial to produce one polypeptide chain comprising a fusion of a two immunogenic polypeptide fragments instead of producing said two immunogenic polypeptide fragments separately.

It will be appreciated that the choice of suitable immunogenic polypeptides and immunogenic polypeptide fragments is far from trivial. Immunogenic polypeptides and immunogenic polypeptide fragments, both individual fragments and fragments comprised in fusion polypeptides, have to be selected taking into account the identity of the polypeptides, identity of the fragments thereof, the individual functionality of said polypeptides and fragments thereof (for example protease activity), their potential interaction (for example in terms degradation), their individual stability in vivo and in vitro, their stability in vivo and in vitro in the form of a fusion polypeptide, their individual solubility in vivo and in vitro, their solubility in vivo and in vitro in the form of a fusion polypeptide, their immunogenic properties, their ability to elicit antibody response of desired kind and their protective properties, just to mention a few.

The skilled person is aware of the fact that in order to elicit an immune response in a subject, an agent with adjuvant properties may be provided to said subject together with one or more immunogenic polypeptides, fragments or fusion polypeptides. Thus, in one embodiment, said immunogenic composition as described herein further comprises an agent with adjuvant effect.

Also within scope of the present disclosure is a vaccine composition for protecting mammalian subjects against infection of S. suis, which comprises an immunogenic composition as described above as immunizing component, and a pharmaceutically acceptable carrier.

As used herein, the term “pharmaceutically acceptable carrier” includes any and all solvents, dispersion media, coatings, surfactants, antioxidants, preservatives (e.g., antibacterial agents, antifungal agents), isotonic agents, absorption delaying agents, salts, preservatives, drug stabilizers, binders, excipients, disintegration agents, lubricants, sweetening agents, flavoring agents, dyes, and the like and combinations thereof, as would be known to those skilled in the art (see, for example, in Alfonso R Gennaro, Remington: The Science and Practice of Pharmacy. 20th edition, ISBN: 0683306472). Examples of pharmaceutically acceptable carriers include, but are not limited to sugars such as lactose, glucose and sucrose; starches such as corn starch and potato starch; cellulose and its derivatives such as sodium carboxymethyl cellulose, ethyl cellulose and cellulose acetate; powdered tragacanth; malt; gelatin; tale; excipients such as cocoa butter and suppository waxes; oils such as peanut oil, cottonseed oil, safflower oil, sesame oil, olive oil, corn oil and soybean oil; glycols such a propylene glycol; esters such as ethyl oleate and ethyl laurate; agar; buffering agents such as magnesium hydroxide and aluminum hydroxide; alginic acid; pyrogen-free water; isotonic saline; Ringer's solution; ethyl alcohol, and phosphate buffer solutions, as well as other non-toxic compatible lubricants such as sodium lauryl sulfate and magnesium stearate.

A pharmaceutically acceptable carrier may be selected from the group consisting of a cream, oil, emulsion (such as a fat emulsion or a lipid emulsion), carbohydrate, cellulose, gel, liposome, nanoparticle, ointment and glycerol, such as the group consisting of a cream, emulsion (such as a fat emulsion or a lipid emulsion), gel, liposome, nanoparticle, ointment and glycerol. A pharmaceutically acceptable carrier may be selected from the group consisting of a cream, emulsion, gel, liposome, nanoparticle and ointment.

Thus, in another aspect of the present disclosure, there is provided a vaccine composition comprising an immunogenic composition as defined herein and a pharmaceutically acceptable carrier or excipient. In one embodiment, said vaccine composition further comprises an agent with adjuvant effect. In one embodiment, said vaccine composition further comprises an immune-effective amount of an agent with adjuvant effect.

As used herein, the term “immune-effective” refers a sufficient amount of an adjuvant to increase the vaccine's immunogenicity to a level high enough to effectively vaccinate a typical patient.

As discussed above, an immunogenic composition and a vaccine composition may comprise an agent with adjuvant effect in an amount that is immuno-effective. Suitably, said adjuvant stimulates systemic or mucosal immunity. The skilled person is aware of suitable adjuvant. Non-limiting examples of suitable adjuvant in the context of the present disclosure include polymers of acrylic or methacrylic acid, maleic anhydride and alkenyl derivative polymers, immunostimulating sequences (ISS), an oil in water emulsion, cation lipids containing a quaternary ammonium salt, cytokines, aluminum hydroxide or aluminum phosphate, saponin or nanoparticles or any combinations or mixtures thereof. Further examples of suitable adjuvants may also be found in literature cited in WO 2007/115059.

A suitable adjuvant for use according to the present invention is the adjuvant Abisco/Matrix M, Matrix C or Matrix Q from Novavax, Sweden.

Another suitable adjuvant is Ginseng. Ginseng is a dry extract prepared from the root of the plant Panax ginseng, C. A. Meyer. Ginseng contains a number of active substances named ginsenosides that are a kind of saponins, chemically tri-terpenoid glycosides of the dammaren series. The ginsenosides have adjuvant properties and one of the most active adjuvants is the fraction named Rb1. It has been proved that the fraction Rb1 elicits a balanced Th1 and Th2 immune response as determined by measuring the levels of the cytokines IFN-γ, IL-2, IL-4, IL-10 secreted post vaccination with a Rb1 adjuvanted vaccine. In addition ginseng and the fraction Rb1 stimulate a strong antigen specific antibody response.

In one embodiment, said agent with adjuvant effect is selected from the group consisting of polymers of acrylic or methacrylic acid, maleic anhydride and alkenyl derivative polymers, immunostimulating sequences (ISS), an oil in water emulsion, cation lipids containing a quaternary ammonium salt, cytokines, aluminum hydroxide, aluminum phosphate, saponin, nanoparticles, silica, Abisco/Matrix M, Matrix C, Matrix Q and silica.

In one particular embodiment, said agent with adjuvant effect is selected from the group consisting of polymers of acrylic or methacrylic acid, maleic anhydride and alkenyl derivative polymers, immunostimulating sequences (ISS), an oil in water emulsion, cation lipids containing a quaternary ammonium salt, cytokines, aluminum hydroxide, aluminum phosphate, saponin, nanoparticles and silica. In one embodiment, said agent in selected from the group consisting of Abisco/Matrix M, Matrix C and Matrix Q. In one particular embodiment, said agent with adjuvant effect is silica.

The vaccine composition of the present disclosure is formulated in form suitable for physiological administration. Thus in one embodiment, there is provided a vaccine composition as described herein formulated for intramuscular, subcutaneous, intradermal or intranasal administration, such as for intramuscular administration.

In one embodiment, the vaccine composition as described herein, is, upon administration, capable of eliciting serum and/or mucosal antibody responses in a mammalian subject, such as a porcine or human subject, such as a porcine subject. In one embodiment, said antibody response is in the form of IgG, IgA and/or IgM antibodies in the serum and/or mucosa.

In one embodiment of the present aspect, there is provided a vaccine composition as described above, for use in the prophylactic treatment of a mammalian subject susceptible to S. suis infection, such as a human subject or porcine subject, such as a porcine subject. According to one embodiment, the vaccine composition is a vaccine that protects susceptible mammalian subjects, such human or porcine subjects, against an infection caused by S. suis.

Suitably, the vaccine composition of the present invention stimulates serum, mucosal and/or bronchial antibody responses directed to S. suis antigens in mammalian subjects susceptible to these bacteria, such as in human or porcine subjects, such as porcine subjects.

As mentioned above, the present disclosure provides a vaccine composition comprising one or several immunogenic polypeptides, immunogenic polypeptide fragments or fusion polypeptides for use as a medicament, which have been prepared according to the present method using E. coli as host cells, however other host cells may be used. The source of the immunogenic polypeptides might also be the native bacteria, if methods are developed for expression and purification thereof. Alternatively, the fusion strategies where various parts of the respective antigen are recombined may be employed resulting in a fusion polypeptides comprised of parts from different immunogenic polypeptides as described herein. This fusion strategy may also be suitable for introducing an immune reactive part(s), e.g. T-cell epitopes or attenuated toxins (or parts thereof), thereby introducing other features suitable for optimizing the antigen presentation or localization.

The present disclosure also relates to a method for the production of an antiserum, said method comprising administering an immunogenic composition as described herein to mammalian host to produce antibodies in said host and recovering antiserum containing the antibodies produced in said animal host. Within the scope of the present disclosure is also an antiserum obtainable by said method.

In a related aspect of the present disclosure, there is provided a method for prophylactic treatment of a S. suis infection in a mammalian subject, comprising administering to said mammalian subject in need thereof an immunologically effective amount of an immunogenic composition as described above, vaccine composition as described above or an antiserum as obtainable by the method described above. In one embodiment, said mammalian subject is a porcine or human subject, such as a porcine subject.

The skilled person will appreciate that many vaccines require administration of more than one dose in order to elicit a protective immune response. The first dose administered to a naïve subject, often referred to as a priming dose, directs the immune system to recognize the foreign antigen. In some cases, the priming dose alone may elicit sufficient protective levels of immunity. However, in other cases the priming dose may not elicit protective levels of immunity. Therefore, priming doses may be followed by one or several subsequently administrations of the identical vaccine in order to increase the magnitude of the antigen specific immune responses. These subsequently administered doses are referred to as boosting doses. Suitably, the elicited immune response is in the form of IgG, IgA and/or IgM antibodies in the mucus and/or serum of piglets or sows/gilts, and/or colostrums of sows.

Thus, in some embodiments, said method for prophylactic treatment comprises administering of an immunologically effective amount of said immunogenic composition, said vaccine composition or said antiserum at one single occasion.

In other embodiments, said method for prophylactic treatment comprises administering of an immunologically effective amount of said immunogenic composition, said vaccine composition or said antiserum at multiple separate occasions, such as two, three, four or more separate occasions. In one embodiment the method for prophylactic treatment comprises administering of an immunologically effective amount of said immunogenic composition, said vaccine composition or said antiserum at two separate occasions. In one embodiment, said administration is of said immunogenic composition or said vaccine composition, such as of said vaccine composition. In one embodiment said multiple separate occasions are at least 2 weeks apart, such as 3-6 weeks apart, such as 3-5 weeks apart, such as 3-4 weeks apart, such as 3 or 4 weeks apart.

In one embodiment, said administration is in an amount of immunogenic polypeptide, immunogenic polypeptide fragment or fusion polypeptide which elicits an immune response resulting in protection. In a particular embodiment, said administration is at a dose in the range of approximately 4-300 μg per immunogenic polypeptide, immunogenic polypeptide fragment or fusion polypeptide. For example, said administration may be in the range of approximately 10-300 μg, such as in the range of approximately 10-250 μg, such as in the range of approximately 10-200 μg, such as in the range of approximately 10-100 μg, such as in the range of approximately 10-80 μg, such as in the range of approximately 10-60 μg, such as in the range of approximately 10-50 μg per immunogenic polypeptide, immunogenic polypeptide fragment or fusion polypeptide. In one embodiment, said dose is in the range of approximately 20-50 μg, such as in the range of approximately 30-50 μg, such as approximately 40 μg per immunogenic polypeptide, immunogenic polypeptide fragment or fusion polypeptide. In another embodiment, said dose is in the range of approximately 10-30 μg, such as in the range of approximately 10-20 μg, such as approximately 16 μg per immunogenic polypeptide, immunogenic polypeptide fragment or fusion polypeptide.

In one embodiment of the method disclosed herein, said administration is to piglets, gilts or sows.

In the case wherein priming dose alone elicits sufficient protective levels of immunity, the administration to piglets may be between postnatal day 1-28. For example said administration may be during the first postnatal week, for example at postnatal day 4. Alternatively, said administration may also be during postnatal week 2, 3 or 4. Thus, in one embodiment, said administration to piglets at one single occasion is during any one of postnatal weeks 1-4, such as any one of postnatal weeks 2-4, such as any one of postnatal weeks 3-4, such as during postnatal week 3 or 4. In one embodiment, said administration is during postnatal week 1.

In embodiments wherein a priming dose and a boosting dose are administered, the first administration to piglets may be during postnatal week 2-4, such as during postnatal week 3-4. In such embodiments, the second administration to piglets is at least 2 weeks after the first administration as described above. For example, the second administration to piglets may be during postnatal week 6-8.

It may be beneficial to make use of the vaccine composition as described herein in a method wherein said vaccine is administrated to a sow or gilt, to protect a piglet through the intake of colostrum from the said sow or gilt, against an infection caused S. suis. Thus in another embodiment of the method disclosed herein, said administration is to pregnant sows or gilts at one or two occasions at a time such as to obtain an immune response in colostrum at time of partum. For example such administration may be on two occasions. In one embodiment, the first administration is to pregnant sows or gilts 6-8 weeks prior to partum and the second administration is 2-4 weeks prior to partum.

Encompassed by the scope of the present disclosure are also antibody preparations comprising at least one, and suitably at least two, antibodies specific for a component of the immunogenic composition as described herein, which antibody/antibodies is/are polyclonal or monoclonal; or which preparation comprises a fragment of said antibodies. It is contemplated that said preparation could be used prophylactically against S. suis and provide passive immunization when administered to a mammalian subject susceptible to S. suis infection.

Thus, in one embodiment of eighth aspect of the present disclosure, there is provided an antibody or fragment thereof, which is specific for an immunogenic polypeptide, immunogenic polypeptide fragment or a fusion polypeptide as described herein, which antibody or fragment thereof is polyclonal or monoclonal. In another embodiment, there is provided an antibody preparation comprising one of several of said antibody/antibodies. Related hereto is a method for prophylactic treatment of a S. suis infection in a mammalian subject, comprising passive immunization by administering to said mammalian subject in need thereof said antibody preparation.

In another aspect of the present disclosure, there is provided the use of an immunogenic peptide, an immunogenic peptide fragment or a fusion polypeptide as described herein, for the manufacture of a medicament for use in the prophylactic treatment of a mammalian subject susceptible to S. suis infection.

As discussed above, an immunogenic composition or a vaccine composition usually requires the presence of an agent with an adjuvant effect for said composition to elicit the desired immune response upon administration to a subject, such as a mammalian subject. The immunogenic composition or a vaccine composition may require the presence of an immune-effective amount of agent with an adjuvant effect for said composition to elicit the desired immune response upon administration to a subject, such as a mammalian subject. Therefore, most immunogenic or vaccine compositions require the additional of an external agent with adjuvant effect. Examples of such agents are listed above. In the context of the present disclosure there is contemplated the use of silica bound via SEQ ID NO:32 (SL2-tag), SEQ ID NO:33 (LSL-tag) or an amino acid sequence with at least 80%-identity to SEQ ID NO:32 or SEQ ID NO:33 to am immunogenic polypeptide, immunogenic polypeptide fragment or fusion polypeptide as disclosed herein as an adjuvant component. The skilled person will appreciated that the said silica-based adjuvant system is not limited to the immunogenic polypeptide, immunogenic polypeptide fragment or fusion polypeptide disclosed herein or to proteins derived from S. suis in general, but may be used with any other immunogenic protein.

The term “silica tag” herein refers to SEQ ID NO:32 (SL2-tag), SEQ ID NO:33 (LSL-tag) or an amino acid sequence with at least 80%-identity to SEQ ID NO:32 or SEQ ID NO:33 and this term is used herein for clarity. Again, the skilled person will appreciate that the above statements regarding sequence identity and %-identity are equally applicable in this context and are not repeated for the sake of brevity.

Thus, in the context of the present disclosure there is contemplated a method for production of an immunogenic mixture with adjuvant properties, comprising

-   -   providing an immunogenic polypeptide construct comprising an         immunogenic polypeptide in fusion with a silica tag as disclosed         herein, which silica tag is capable of binding to silica, and     -   bringing said construct in contact with silica,         thereby obtaining an immunogenic mixture with adjuvant         properties. Herein the immunogenic polypeptide construct is         under physiological conditions, is associated to silica via said         tag, which silica is capable of providing adjuvant properties.

In one embodiment, there is provided a method for production of an immunogenic mixture with adjuvant properties, wherein said step of providing an immunogenic polypeptide construct comprises

-   -   providing an expression vector comprising a polynucleotide         encoding said immunogenic polypeptide in fusion with said silica         tag in a suitable host cell,     -   culturing said host cell under conditions permissive of         expression of said immunogenic polypeptide in fusion with said         silica tag, and     -   isolating said immunogenic polypeptide in fusion with said         silica tag.

In one embodiment of said method, said immunogenic polypeptide construct is provided in a bacterial lysate.

In one embodiment, said method further comprising purifying said immunogenic polypeptide construct.

In one embodiment of said method, said step of bringing said immunogenic polypeptide construct in contact with silica comprises mixing said lysate with silica.

In one embodiment, said method comprises allowing said immunogenic polypeptide construct to bind to silica at a pH-value in the range of pH 5-10, such as in the range of pH 6-9. In one embodiment, said method comprises allowing said immunogenic polypeptide construct to bind to silica at low salt conditions, such as at a salt concentration in the range of 5-50 mM, such as in the range of 10-20 mM. In one embodiment said method further comprises purifying said immunogenic polypeptide construct based on the affinity of said tag for silica. In one embodiment, said purification comprises a step of gravity based separation (for example by centrifuging the mixture of said immunogenic polypeptide construct and silica), whereby separating said immunogenic polypeptide construct bound to silica from unbound polypeptides.

In one embodiment, said method further comprises the sonication of said immunogenic polypeptide construct bound to silica.

In one embodiment of said method, said silica has an average diameter in the range of approximately 5 nm-0.5 μm, such as a diameter in the range of approximately 0.2-0.3 μm or a diameter of approximately 7 nm. Also encompassed by the present disclosure are immunogenic mixtures with adjuvant properties, obtainable by the method described herein; immunogenic polypeptides in fusion with said silica tag; immunogenic polypeptides in fusion with said silica tag, which are bound to silica; immunogenic polypeptide in fusion with said silica tag for use in prophylactic therapy; polynucleotide encoding said polypeptides; expression vectors comprising said polynucleotides; host cells comprising said expression vectors.

Also encompassed by the present disclosure is said silica tag per se, which tag corresponds to SEQ ID NO:32, SEQ ID NO:33 or an amino acid sequences with at least 80%-identity to SEQ ID NO:32 or 33. For the sake of clarity, silica tags as disclosed herein are equally suitable as N-terminal and C-terminal tags. Kits comprising an immunogenic polypeptide in fusion with said silica tag and silica are also contemplated.

While the invention has been described with reference to various exemplary aspects and embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or molecule to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to any particular embodiment contemplated, but that the invention will include all embodiments falling within the scope of the appended claims.

BRIEF DESCRIPTION OF FIGURES

FIG. 1A-E shows schematic drawings of expression vectors used in this disclosure; (A) pPGex-6P-1, (B) pBmA, (C) pBmK, (D) pBmKny, (E) pBmKSL2 and (F) pBmKLSL.

FIG. 2 is a schematic drawing of the four proteins chosen as vaccine candidates. Characteristic features of the proteins are indicated and the boarder for each domain is based on NCBI blast search and NCBI conserved domains. The bars below each gene indicate separate protein fragment that have been expressed and purified. Abbreviations: SP=signal peptide, MA=membrane anchor, LPXTG=cell wall anchor motif, MpD=metallophosphatase domain, NuD=nucleotidase domain.

FIG. 3 shows the results of an SDS-PAGE analysis of eight His-tagged recombinant S. suis protein fragments: M2N—H, M2C—H, SP2N—H, SP2C—H, SP4N—H, SP4C—H, SP7N—H and SP7C—H. Molecular weight markers (kDa): 97, 66, 45, 30, 20.1 and 14.4.

FIG. 4 shows the results of an SDS-PAGE analysis of E. coli lysates from eight clones expressing C-terminal SL2-tagged recombinant S. suis protein fragments M2N—S, M2C—S, SP2N—S, SP2C—S, SP4N—S, SP4C—S, SP7N—S, SP7C—S.

FIG. 5 shows the results of an SDS-PAGE analysis of recombinant S. suis protein fragments M2N—S, SP2C—S, SP4C—S and SP7C—S bound to silica particles. As a comparison E. coli lysates from respective clone are also shown.

FIG. 6 shows the results of an SDS-PAGE analysis of recombinant S. suis protein fragments using a modified silica tag (LSL). This figure also shows that proteins which are not derived from S. suis can be purified using a silica tag. In addition SP2C—H (no silica tag) does not bind to silica showing the importance of the affinity tag in binding to silica.

FIG. 7 shows the results of purification of the SL2-tagged fusion polypeptides SP74C—S and SP2M2-S using silica. (A) Gel electrophoresis analysis of DNA bound to silica particles using various number of washing. Analysis was performed by electrophoresis using a 1% agarose gel. (B) SDS-PAGE analysis of silica bound fusion polypeptides using the same washing procedure as in A.

FIG. 8 shows the results of a comparison of Talon purified His-tagged recombinant S. suis protein fragments M2N—H, SP2C—H, SP4C—H and SP7C—H and Q-Sepharose ion exchange chromatography purified SL2-tagged recombinant S. suis protein fragments M2N—S, SP2C—S, SP4C—S and SP7C—S using SDS-PAGE.

FIG. 9 shows the results of an analysis of the stability of Q-Sepharose purified antigens M2N—S, SP2C—S, SP4C—S and SP7C—S using SDS-PAGE.

FIG. 10 shows the results of an analysis of the Q-Sepharose purified fusion polypeptides SP2M2-S and SP74C—S using SDS-PAGE. The purified fusion polypeptides are shown in FIG. 9A. FIG. 9B shows the two fusions when mixed and incubated at 37° C. compared to frozen samples.

FIGS. 11A, B, C and D are bar graphs showing the results of the ELISA analysis on days 0 (pre-imm average) and 35 (day 35 average) of the mouse immunizations with SP2C—S, SP4C—S, SP7C—S and M2N—S, respectively, described in Example 9. Mean values (n=3) and standard errors are shown.

FIGS. 12A and B shows bar graphs showing the results of the ELISA analysis of serum samples obtained at day 0, 7, 14, 21 and 28 from piglets immunized two times with SP2M2-S and SP74C—S as described in Example 11. Mean values and standard errors are shown. The indication “—S” has been omitted in the graph.

FIG. 13 shows the amino acid sequences of the polypeptides disclosed herein. In particular in SEQ ID NO:13-31, note that amino acids in bold originate from vector and cloning site and italicized amino acids indicate either a His-tag, SL2-tag or LSL-tag sequence. In SEQ ID NO:34-37 and 107-110, note that the amino acids in bold originate from the construction work of the fusion polypeptide and that these amino acids could be changed or even absent if another fusion strategy is used.

FIGS. 14A and B is a graph showing the rectal temperatures and demeanor score of animals vaccinated with SP274C—S and control animal (adjuvant only) as measured at study days 26/30 to 34/38. SP274C—S is abbreviated SP274 in the figure.

FIGS. 15A and B is a graph showing the behavior score and mobility score scores of animals vaccinated with SP274C—S and control animal (adjuvant only) as measured at study days 26/30 to 34/38. SP274C—S is abbreviated SP274 in the figure.

FIG. 16 is a graph showing the total score of animals vaccinated with SP274C—S and control animal (adjuvant only) as measured at study days 26/30 to 34/38.

FIGS. 17A and B are bar graphs showing the IgG-antibodies against SP274C—S in piglets vaccinated with SP274C—S and control piglets measured on day 1 and day 31 of the study. SP274C—S is abbreviated SP274 in the figure.

FIG. 18 shows the added clinical score for piglets vaccinated with SP274C—S and control piglets administered placebo.

EXAMPLES

In the following examples the identification, cloning and purifications of antigen fragments for use in a vaccine against S. suis infection is disclosed. Also disclosed is data from immunization of mice with said fragments and immunization and vaccine studies in porcine subjects using said fragments, combinations of said fragments and fusion polypeptides comprising said fragments.

Materials and Methods

The molecular work has been done according to the information in “Molecular Cloning: A Laboratory Manual” by J. Sambrook, E. F. Fritsch, T. Maniatis. The different methods used are described in short below.

Electroporation of E. coli: In all instances the strain E. coli BL21 have been used as recipient of plasmids. 1 μl of plasmid was added to 50 μl of electrocompetent cells (on ice) and the mixture was transferred to cold cuvettes (1 mm gap). The conditions for the electroporation were; 200-400 ohm, 25 microfarad and 2.5 kV. After the electroporation the cells were resuspended in 1 ml LB-medium and incubated for one hour at 37° C. (phenotypic expression) after which the cells are spread on LB-plates with the appropriated antibiotics.

Ligations: The ligations were performed using T4 DNA ligase (New England Biolabs) in a DNA concentration of approximately 20-50 μg/ml for at least one hour. Thereafter the DNA was EtOH precipitated, washed with 70 EtOH and dried. The pellet was dissolved in H₂O and used for electroporation.

Purification of DNA: For plasmid purification, an overnight growth culture of E. coli BL-21 was harvested of which 2-4 ml was used for plasmid preparation. The plasmid was purified using QIAprep Spin Miniprep kit (Qiagen) according to the supplier's instructions. Purification of DNA after CIP treatment of PCR products was done by using QIAquick PCR purification kit (QIAGEN).

Cleavage with restriction enzymes: The appropriated buffer was added to the DNA and DTT (Dithiothreitol; Amersham Biosciences) was added to a final concentration of 1 mM. Thereafter the restriction enzyme(s) (New England Biolabs) was added to a concentration of 2-10 units/μg and the mixture was incubated for 2-3 hours.

CIP treatment of vectors: All vectors used for cloning were treated with Calf Intestinal Alkaline Phosphatase (CIP) (New England Biolabs) for one hour in the same buffer used for restriction enzyme cleavage. Thereafter the vector was purified using QIAquick PCR purification kit (QIAGEN).

PCR conditions: Fidelity Taq PCR Master Mix (USB, Affymetrix) was been used according to the instructions. If not stated otherwise, the annealing temperature has been 5-10° C. under the melting point for the primers, the number of cycles has been 30 and the extension time has been approximately 1 minute per 1 kbp of DNA.

DNA sequencing:

All DNA sequencing was performed by the Uppsala Genome Center Sequencing Service (Uppsala, Sweden).

SDS-Page Analysis:

SDS-PAGE analyses were performed using the PhastSystem (GE-Healthcare). Samples were analyzed under reducing conditions using precasted 8-25% gradient gels.

Expression of recombinant proteins: In general, similar conditions have been used for all proteins expressed in this application. A single colony was inoculated into 20-30 ml LB medium supplemented with kanamycin (25-50 μg/ml) and the culture was incubated while shaking over night at 25° C. From the overnight culture 10-20 ml was inoculated into 11 LB supplemented with kanamycin (25-50 μg/ml) and the culture was incubated with shaking at 25° C. for a few hours (5-7 hours). The expression of recombinant protein was induced by addition of 11 LB supplemented with kanamycin (25-50 μg/ml) and 0.2 mM isopropyl β-D-1-thiogalactopyranoside (IPTG) and the culture was incubated while shaking over night at 25° C.

Protein Lysate:

After the induction phase, the culture was harvested by centrifugation and the cells are resuspended in lysis buffer (100 mM NaCl, 20 mM Tris (pH 7-7.5) and 0.05% Tween 20) and 10-100 μg/ml lysozyme was added after which the cells were lysed using freeze/thaw cycles. The lysate was then sonicated (40-60% amplitude) on ice-water for 2×10 minutes with 1 second pulses. The lysate was centrifuged for 20-30 minutes at 10K RPM. The supernatant was collected and sterile filtered (using a 0.45 μm filter) after which the lysate was frozen in aliquots.

Silica:

Silica fumed 0.2-0.3 μm (article number S5505) and Silica fumed 0.007 μm (article number S5130) was purchased from Sigma (St. Louis, USA). Silica fumed 0.2-0.3 μm was used for all protein purifications and also used as adjuvant for mouse immunization. Silica fumed 0.007 μm was used as adjuvant for mouse immunization. Before use, stock solutions were made from the silica powders by adding silica powder to a volume corresponding to 40 ml. The powder was prepared into a slurry in 40 ml H₂O.

In weight, 40 ml silica fumed 0.2-0.3 μm corresponds to approximately 1 gram and 40 ml silica fumed 0.007 μm corresponds to approximately 2 gram. The protein purification using silica was performed using approximately 1/10 volume of silica slurry and 1/10 volume of protein lysate and 1/50 volume Tris (1 M, pH 9) and 8/10 volume H₂O supplemented with 0.02% Tween 20 was added. The protein binding to silica was performed for a few hours or overnight with slow shaking, after which the silica was collected by centrifugation and washed.

The silica slurry used in immunization experiments was pretreated by sonication and autoclaving before mixing with the purified proteins.

Construction of Plasmid Vectors

Construction of Plasmid Vector pBmA:

The plasmid pGex6p-1 (GE-Healthcare) was used as a scaffold for the construction of the expression plasmids (FIG. 1A). The first step in construction of the expression plasmid was to exchange the domain encoding the GST-polypeptide for a synthetic DNA fragment using the restriction sites BtgI and AatII. The synthetic DNA fragment BmT (SEQ ID NO:87) was synthesized by GenScript (Piscataway, USA) and contains the tac-promoter with 5′-flanking sequences, a translation enhancer element (AT-rich DNA) just upstream of the ribosomal binding site, cloning sites (BamHI, EcoRI, SnaBI and XhoI), translational stop codons and a transcriptional termination sequence (from His-operon in E. coli). The BmT fragment is flanked by the restriction enzyme site BtgI and AatII and after cleavage with these enzymes the fragment was ligated into pGex-6P-1 (cleavage with BtgI and AatII). The vector obtained is called pBmA (SEQ ID NO:59) (FIG. 1B).

Construction of the pBmK Plasmid:

The pBmK vector (SEQ ID NO:60) was made from the pBmA vector with the main difference that the β-lactamase gene is exchanged with a gene encoding kanamycin resistance.

The pBmA vector was digested with AatII and DraI and a PCR fragment containing the kanamycin gene was ligated into the cleaved vector. As a template to obtain the kanamycin gene, the plasmid pJexpress 401 (obtained from DNA2.0 (Menlo Park, Calif., USA)) was used. The primers used to amplify the kanamycin resistance gene are called “kana1” and “TR2 mod” (Table 1). TR2 mod also contains a transcriptional terminator sequence. The new vector was called pBmK and a schematic drawing of the plasmid is shown in FIG. 1C.

Construction of the pBmKny Vector:

The main reason for constructing the new vector, called pBmKny (SEQ ID NO:61) (FIG. 1D), was a repetitive DNA sequence present two times in pBmK. This sequence “GTGTGGAATTGTGAGCGGATAACAATTTCACA” is located just after the LacI gene and in the Tac-promoter. The copy located after the LacI gene was removed and also the distance between the LacI gene and the cloning cassette is shortened and a transcriptional termination sequence (from phage T7Te) is added just downstream the LacI gene. The BmKny vector was made by joining two DNA fragments using the restriction sites AatII and HindIII. One DNA fragment was a PCR-product of pBmK from the AatII including the LacI gene with the 3″-primer containing the restriction enzyme site HindIII (primers BmaatII and LacIRev (Table 1)). The other fragment was a synthetic DNA Kny (SEQ ID NO:88) (obtained from Genescript) containing a transcriptional termination sequence (T7Te), Tac-promoter, translation enhance element (AT-rich DNA) upstream of the ribosomal binding site, cloning-sites and a transcriptional termination sequence. This fragment was flanked by the restriction sites HindIII and AatII. The DNA fragment is very similar to the one in pBmK with the following differences; one extra nucleotide is added between the ribosomal binding site and the translation start codon, one nucleotide is changed in proximity of the start-codon which results in a NdeI-site, and the cloning site SnaBI is removed.

Construction of the BmKSL2 Vector:

The vector BmKSL2 (SEQ ID NO:62) was made by insertion of synthetic DNA called SL2 (SEQ ID NO:90) (obtained from GenScript) into pBmKny, using the restriction sites XhoI and SpeI (FIG. 1D). The SL2 fragment encodes a 22 amino acid tag that binds to silica (SEQ ID NO:32). The silica binding tag SL2 corresponds to the C-terminal part of ribosomal protein L2 from S. suis. The ribosomal protein L2 from E. coli has earlier been shown to bind silica (Taniguchi et al (2007) Biotechnol Bioeng; April 15; 96(6):1023-9) and the main binding domain in L2 is located in the C-terminal part (Li et al (2013), Appl Microbiol Biotechnol, March; 97(6):2541-9 and Li et al (2013), J Chromatogr B Analyt Technol Biomed Life Sci, February 15; 917-918:30-5). The C-terminal 22 amino acids part of L2 from E. coli and S. suis exhibit 55% sequence identity and contain a high number of positively charged amino acids. Positively charge stretches of amino acids such as poly-arginine have earlier been shown to bind to silica (Fuchs and Raines (2005), Protein Sci. June; 14(6):1538-44).

Construction of the BmKCHis Vector:

The BmKCHis vector (SEQ ID NO:63) encodes seven histidines immediately downstream of the XhoI site. The vector was constructed by annealing the two oligonucleotides C1his and C2his together followed by ligation into the vector BmKny cleaved with the restriction enzymes XhoI and SpeI.

Construction of the BmKLSL Vector:

The BmKLSL (SEQ ID NO:64) vector contains a variant of the SL2-tag, denoted LSL-tag (SEQ ID NO:33), which variant is 4 amino acid longer and is located directly upstream of the cloning site BamHI (FIG. 1E). The vector was made by insertion of a PCR fragment into the NdeI and BamHI sites in the BmKny vector. The fragment was obtained by PCR using BmKSL2 as template and the primers used was LSLs and LSLr.

TABLE 2 List of primers/oligonucleotides used herein. SEQ ID NO: Name Sequence 5′-3′ 65 kana1 ATATGACGTCAGGTGGGACCACCGCGCTAC 66 TR2mod GCGTTTTAAAAAAAAACGCGGTCGATTACCCG ACCGCGAAAGGTTTTGCGCCATTCG 67 BmaatII ATATGACGTCAGGTGGGACCAC 68 LacIRev ATATAAGCTTGGTGCCTAATGAGTGAGCTAAC 69 C1his TCGAGCATCACCATCACCATCACCATTAAA 70 C2his CTAGTTTAATGGTGATGGTGATGGTGATGC 71 LSLs ATATCATATGACAAAACCTGCACTGGGACTGA AGACCCGC 72 LSLr TATAGGATCCCTTCTGATTGCGACGGCG 73 M2p1 ATATGGATCCGATACGGTAGTAACGGGTG 74 M2p3 TATACTCGAGATTGAAATACTCTTCCCACAG 75 sp2CBam ATATGGATCCGACGAAATCAAAGCAAAATACG 76 Sp2CXhoVal TATACTCGAGACCTGCTTTGGTCGTTTTTGC 77 Tac5 GCCGACATCATAACGGTTCTGG 78 SP2CKpnI TATAGGTACCACCTGCTTTGGTCGTTTTTGC 79 NMAKpn ATATGGTACCGATACGGTAGTAACGGGTG 80 NP7Kpn TATAGGTACCGGTTTGGTTGCCACTTGC 81 SP4CKpnI ATATGGTACCGGCGAAACGACGGC 82 BmR2 GGTGGTCCCACCTGACGTC 83 M2p4 ATATGGATCCAGCGAGCAGCCGGACAG 84 M2p5 TATACTCGAGGCTGCTCACCGCGGTC 85 sp2NXho-H TATACTCGAGGTCGACCAGTGCGGCG 86 Sp4NXho TATACTCGAGCGTGGTTTCACCGACTTGC

Primers used in the experiments described in the following examples are shown in Table 2 above.

Example 1 General Description of Antigens Chosen

Four surface proteins encoded by S. suis were chosen as candidates for vaccine trials. The genes encoding these proteins are SSU0496 (SEQ ID NO:1), SSU0860 (SEQ ID NO:2), SSU1879 (SEQ ID NO:3) and SSU1355 (SEQ ID NO:4) and the encoded proteins are expressed by many different strains and serotypes of S. suis (Gómez-Gascóna et al, supra) and are conserved in the publically available databases (NCBI and Welcome Trust Sanger Institute). In the context of the present disclosure said S. suis proteins are denoted according to the following: SSU0496 is denoted M2 (SEQ ID NO:1), SSU0860 is denoted SP2 (SEQ ID NO:2), SSU1879 is denoted SP4 (SEQ ID NO:3) and SSU1355 is denoted SP7 (SEQ ID NO:4). The version of the genes used in herein corresponds to the sequence of S. suis strain P1/7

(Welcome Trust Sanger Institute).

A schematically drawing of M2, SP2, SP4 and SP7 is shown in FIG. 2. Characteristic features of the proteins are indicated and the boarder for each domain is based on NCBI blast search and NCBI conserved domains. The bars below each gene indicate separate protein fragments that have been expressed and purified.

Example 2 Expression and Purification of Fragments of M2, SP2, SP4 and SP7 from S. suis

This Example describes the cloning, expression and purification of two fragments of each of the antigens M2, SP2, SP4 and SP7 in fusion with a His-tag. The size of said fragments was confirmed by SDS-PAGE analysis.

Material and Method:

The fours antigens M2 (SEQ ID NO:1), SP2 (SEQ ID NO:2), SP4 (SEQ ID NO:3), and SP7 (SEQ ID NO:4) were expressed as an N-terminal and a C-terminal fragment and denoted as follows M2N, M2C, SP2N, SP2C, SP4N, SP4C, SP7N and SP7C, corresponding to SEQ ID NO:5, 6, 7, 8, 9, 10, 11 and 12, respectively. The gene fragments were obtained from external providers as indicated below and cloned into the BmKny vector in fusion with 6 histidines (indicated herein by the letter H) according to the following:

pM2N—H:

M2 was ordered codon optimized from DNA 2.0. The N-terminal part of the gene was amplified by PCR and cloned into the vector BmKCHis (SEQ ID NO:63) using the restriction enzyme sites BamHI and XhoI. The PCR conditions were 52° C. annealing temperature, 2 minutes extension and 30 cycles, using the codon optimized DNA as a template and the primers M2p1 and M2p3. The obtained His-tagged polypeptide is denoted M2N—H (SEQ ID NO:13).

pM2C—H:

M2 was ordered codon optimized from DNA 2.0. The gene was used as a template with the primers M2p4 and M2p5 in a PCR reaction. The product was cleaved with the restriction enzymes BamHI and XhoI and cloned into the vector BmKCHis cleaved with the corresponding enzymes. The obtained His-tagged polypeptide is denoted M2C—H (SEQ ID NO:14).

pSP2N—H:

The SP2N gene fragment was ordered codon optimized from GenScript. The DNA fragment contains the restriction enzymes site BamHI and XhoI and a DNA sequence encoding six histidines before the XhoI site. This fragment was cleaved with BamHI and XhoI and ligated into the vector BmKny in the corresponding sites. The obtained His-tagged polypeptide is denoted SP2N—H (SEQ ID NO:15).

pSP2C—H:

The gene fragment SP2C was ordered codon optimized from GenScript and was flanked by the restriction enzymes sites BamHI and XhoI. In addition, the fragment encodes six histidines after the BamHI site. The fragment was cloned into the vector BmKny using the sites BamHI and XhoI. The obtained His-tagged polypeptide is denoted SP2C—H (SEQ ID NO:16).

pSP4N—H:

The SP4N gene fragment was ordered codon optimized from GenScript. The DNA fragment contains the restriction enzymes site BamHI and XhoI and a DNA sequence encoding six histidines just before the XhoI site. This fragment was cleaved with BamHI and XhoI and ligated into the vector BmKny in the corresponding sites. The obtained His-tagged polypeptide is denoted SP4N—H (SEQ ID NO:17).

pSP4C—H:

The SP4C gene fragment was ordered codon optimized from GenScript and was flanked in the N-terminal by the restriction enzymes site NdeI followed by a DNA sequence encoding six histidines after which a BamHI site follows and the C-terminal ends with the restriction site XhoI. The fragment was cleaved with NdeI and XhoI and cloned into the vector BmKny in the corresponding sites. The obtained His-tagged polypeptide is denoted SP4C—H (SEQ ID NO:18).

pSP7N—H:

The SP7N gene fragment was ordered codon optimized from GenScript and was flanked by the restriction enzymes site BamHI and XhoI. The fragment was cleaved with BamHI and XhoI and ligated into the vector BmKCHis in the corresponding sites. The obtained His-tagged polypeptide is denoted SP7N—H (SEQ ID NO:19).

pSP7C—H:

The SP7C gene fragment was ordered codon optimized from GenScript and was flanked N-terminally by the restriction enzymes site NdeI followed by a DNA sequence encoding six histidines after which a BamHI site follows and the C-terminal ends with the restriction site XhoI. The fragment was cleaved with NdeI and XhoI and cloned into the vector BmKny in the corresponding sites. The obtained His-tagged polypeptide is denoted SP7C—H (SEQ ID NO:20).

The E. coli clones were grown and the protein expression induced after which protein lysates was made and purified on Talon columns and analyzed by SDS-Page as described above.

Results:

A SDS-PAGE gel with the eight purified His-tagged protein fragments is shown in FIG. 3. The sizes of most proteins correspond well to the predicted size. It was observed that M2C—H migrates slower than expected which may be due to that it forms a dimer. Several fragments of different sizes of SP7N—H were observed and most likely represent breakdown products. The protein fragment SP4C—H was difficult to purify due to its high tendency to precipitate.

In conclusion, we were able to successfully express and purify the fragments M2N, M2C, SP2N, SP2C, SP4N, SP4C, SP7N and SP7C in fusion with the His-tag.

Example 3 Expression of Fragments of M2, SP2, SP4 and SP7 Fused to an SL2-Tag

This Example describes the cloning, expression and purification of two fragments of each of the antigens M2, SP2, SP4 and SP7 in fusion with the SL2-tag (SEQ ID NO:32). The size of said fragments was confirmed by SDS-PAGE analysis.

Material and Method:

The eight gene fragments encoding the protein fragments M2N, M2C, SP2N, SP2C, SP4N, SP4C, SP7N and SP7C were cloned into the Bm Kny vector in fusion with the SL2-tag (GLKTRNKKAKSDKLIVRRRNQK (SEQ ID NO:32)), indicated herein by the letter S and located in the C-terminus according to the following:

pM2N—S:

For cloning of MN2-S the same PCR product was used as for M2N—H. It was ligated into the vector BmKSL2 using the sites BamHI and XhoI. The obtained SL2-tagged polypeptide is denoted M2N—S(SEQ ID NO:21).

pM2C—S:

A codon optimized version of the gene M2 was made by DNA2.0. The gene was used as a template with the primers M2p4 and M2p5 in a PCR. The product was cleaved with the restriction enzymes BamHI and XhoI and cloned into the vector BmKSL2 cleaved with the said enzymes. The obtained SL2-tagged polypeptide is denoted M2C—S(SEQ ID NO:22).

pSP2N—S:

The SP2N gene fragment, lacking the region encoding six histidines, was cloned into the vector BmKSL2 using the sites BamHI and XhoI. The DNA fragment cloned was obtained by PCR using the SP2N—H clone as template with the primers Tac5 and sp2NXho-H. The obtained SL2-tagged polypeptide is denoted SP2N—S(SEQ ID NO:23).

pSP2C—S:

To clone the SP2C gene fragment into the BmKSL2 vector the fragment was amplified by PCR using the primers sp2CBam and sp2CXho-Val and as template the DNA from the SP2C—H clone was used. The PCR conditions were 52° C. annealing temperature, 2 minutes extension and 30 cycles. The PCR product was cleaved with enzymes BamHI and XhoI and ligated into the corresponding sites in the BmKSL2 vector. The obtained SL2-tagged polypeptide is denoted SP2C—S(SEQ ID NO:24).

pSP4N—S:

The SP4N gene fragment, lacking the region encoding six histidines, was cloned into the vector BmKSL2 using the sites BamHI and XhoI. The DNA fragment cloned was obtained by PCR using the SP4N—H clone as template with the primers tac5 and sp4NXho. The obtained SL2-tagged polypeptide is denoted SP4N—S(SEQ ID NO:25).

pSP4C—S:

The same SP4C gene fragment as described in connection with SP4C—H was used for cloning. It was cleaved with the restriction enzymes BamHI and XhoI and ligated into the vector BmkSL2 in the corresponding sites. The obtained SL2-tagged polypeptide is denoted SP4C—S (SEQ ID NO:26).

pSP7N—S:

The same SP7N gene fragment as described in connection with SP7N—H was used for cloning. It was cleaved with BamHI and XhoI and ligated into the vector BmKSL2 in the corresponding sites. The obtained SL2-tagged polypeptide is denoted SP7N—S(SEQ ID NO:27).

pSP7C—S:

The same SP7C codon optimized gene fragment as described in connection with SP7C—H was used for cloning. It was cleaved with the restriction enzymes BamHI and XhoI and ligated into the vector BmkSL2 in the corresponding sites. The obtained SL2-tagged polypeptide is denoted SP7C—S(SEQ ID NO:28).

The E. coli clones were grown and the protein expression induced after which protein lysates were made and analyzed using SDS-PAGE as described above.

Results:

A SDS-PAGE gel of eight lysates of E. coli expressing the SL2-tagged protein fragments is shown in FIG. 4. The sizes of the most prominent band (corresponding to the expressed SL2-tagged protein fragments) correspond well to the predicted size. The M2C—S protein migrates approximately like a dimer as it did in fusion with the His-tag. The expression of some of the protein is very high. In general, the expression levels of the C-terminal part of the three nucleotidases is higher than the N-terminal parts. In conclusion, we were able to successfully express—the fragments M2N, M2C, SP2N, SP2C, SP4N, SP4C, SP7N and SP7C in fusion with the SL2-tag.

Example 4 Purification of Protein Fragments with SL2-Tag on Silica

In this Example the purification of a subset of SL2-tagged proteins fragments is described.

Material and Method:

Lysates of clones M2N—S, SP2C—S, SP4C—S and SP7C—S (corresponding to SEQ ID NO:21, 24, 26 and 28, respectively) were used. Silica was prepared as described above. The binding to silica were performed under low salt concentration to minimize the binding of other proteins to the silica particles. The binding to silica was performed using 0.1 ml protein lysate, 20 μl Tris (1 M, pH 9), 0.15 ml silica solution (0.2-0.3 μm) and 0.8 ml H₂O supplemented with 0.02% Tween 20. The mixture was shaken slowly over night at room temperature. After binding, silica was collected by centrifugation for a few seconds and washed two times in 1 ml buffer (20 mM Tris, pH 7.3 and 20 mM NaCl) supplemented with 0.02 Tween 20. The volumes of the silica pellet were dissolved in total up to 0.1 ml and an aliquot was mixed with SDS gel loading buffer and analyzed by SDS-PAGE.

Results:

This example shows that different proteins fused to the SL2-tag may be purified on silica (FIG. 5).

Example 5 Purification of Protein Fragments with LSL-Tag or SL2-Tag on Silica

In this example, an N-terminal version of the SL2-tag is used for purification of two protein fragments (M2N, SP2C) and the SL2-tag is used for the purification of IdeE (S. equi), a protein from a different bacterial species.

Material and Method:

The modified tag version, called LSL (KPALGLKTRNKKAKSDKLIVRRRNQK) (SEQ ID NO:33), is four amino acids longer than the SL2-tag, and was engineered so that it is located at the N-terminal end of the fusion polypeptide. M2N and SP2C were cloned into the BmKLSL vector in fusion with the LSL-tag located in the N-terminal while a codon optimized version of IdeE (S. equi) (Lannergård and Guss (2006) FEMS Microbiol Lett. September; 262(2):230-5 (Accession number: ABF57910.1)) was cloned into BmKSL2 vector in fusion with the SL2-tag located in the C-terminal according to the following:

pM2N-LSL:

To make the M2N-LSL construct, the same PCR product was used as for the cloning of M2N—H. The cleaved PCR product was ligated into the vector BmKLSL cleaved with BamHI and XhoI. The obtained LSL-tagged polypeptide is denoted M2N-LSL (SEQ ID NO:29).

pSP2C-LSL:

To make the SP2C-LSL construct, the same PCR product was used as for the cloning of SP2C—H. The cleaved PCR product was ligated into the vector BmKLSL cleaved with BamHI and XhoI. The obtained LSL-tagged polypeptide is denoted SP2C-LSL (SEQ ID NO:30).

pldeE-S:

A codon optimized version of IdeE (S. equi) (Accession number: ABF57910.1) obtained from DNA2.0 was used. The IdeE (S. equi) gene was flanked by the sites BamHI and XhoI and was cloned into the vector BmKSL2 using the restriction sites BamHI and XhoI. The obtained SL2-tagged polypeptide is denoted IdeE-S(SEQ ID NO:31).

Recombinant proteins were expressed in E. coli and protein lysates were obtained as described above.

The binding to silica was performed by using 0.1 ml protein lysate, 20 μl Tris (1 M, pH 9), 0.1 ml silica slurry (0.2-0.3 μm) and 0.8 ml H₂O supplemented with 0.02% Tween 20. The binding was performed with slow shaking for five hours. Next, the silica were collected by centrifugation for a few seconds and washed two times in 1 ml buffer (20 mM Tris, pH 7.3 and 20 mM NaCl) supplemented with 0.02% Tween 20. The volumes of the silica pellets were dissolved in total up to 0.1 ml and an aliquot was analyzed using SDS-PAGE.

Results:

Both M2N-LSL (SEQ ID NO:29) and SP2C-LSL (SEQ ID NO:30) can be purified on silica. The example also shows the purification of protein IdeE-S(SEQ ID NO:31). IdeE is a protein derived from S. equi and is included herein to show that proteins that are not S. suis proteins can be purified on silica using the SL2-tag. Importantly, SP2C comprising a His-tag (SP2C—H (SEQ ID NO:16) does not bind to silica, demonstrating that the SL- or LSL-tag is required for binding to silica. This data shows that silica tags, such as SL or LSL are useful for the purification of various proteins irrespective of origin. Additionally, a silica tag used for purification may be N-terminally or C-terminally located in the proteins to be purified.

Example 6 Cloning of Fusion Polypeptides and Purification Thereof Using the SL2-Tag

In this Example, the cloning of fusion polypeptides comprising SP2C and M2N, referred to herein as SP2M2 (SEQ ID NO:34), as well SP4C and SP7C, referred to herein as SP74C (SEQ ID NO:35) is described. Also described is the silica based purification of said fusion polypeptide with an SL2-tag. Additionally, fusion proteins comprising three immunogenic fragments (such as SP274C (SEQ ID NO:107) SP742C (SEQ ID NO:108)) are in fusion with SL2-tag (SEQ ID NO:109 and SEQ ID NO:110) are disclosed herein.

Cloning of Fusion Polypeptide SP2M2:

The SP2M2 construct (SEQ ID NO:34) is a fusion of the gene fragments SP2C and M2N. The SP2C fragment was PCR amplified using the template Sp2C—S(SEQ ID NO:24) and the primers Tac5 and SP2CKpnl. The M2Nlong fragment (SEQ ID NO:38) was PCR amplified using the codon optimized version template M2 (SEQ ID NO:1) and primers NMAKpn and CLMAXho. The PCR condition for the two reactions was 50° C. annealing temperature, 2 minutes extension and 30 cycles. The SP2C PCR product was digested with BamHI and KpnI and the M2N PCR product was digested with KpnI and XhoI. The digested fragments were ligated into the vector BmKSL2 digested with BamHI and XhoI.

The M2Nlong fragment (SEQ ID NO:38) in this fusion is 6 amino acids longer (PLAKAK) than in the M2N fragment (SEQ ID NO:2) in the M2N—S construct (SEQ ID NO:21). The two lysines in close connection to the SL2-tag were thought to improve the binding to silica.

Cloning of Fusion Polypeptide SP74C:

The SP74C construct (SEQ ID NO:35) is a fusion of the gene fragments SP7C and SP4C. The SP7C fragment was PCR amplified using the template SP7C—S(SEQ ID NO:28) and primers Tac5 and NP7Kpn. The SP4C fragment was PCR amplified using the template SP4C—S(SEQ ID NO:26) and primers SP4CKpnl and BmR2. The PCR condition for the two reactions was 50° C. annealing temperature, 2 minutes extension and 30 cycles. The SP7C PCR product was digested with BamHI and KpnI and the SP4C PCR product was digested with KpnI and XhoI. The cleaved fragments were ligated into the vector BmKSL2 digested with BamHI and XhoI.

Lysis:

Recombinant proteins were expressed in E. coli as described above. The procedure of making a bacterial lysate includes a step with sonication for several minutes. This step results in fragmentation of chromosomal DNA and plasmid DNA, which makes any DNA binding to silica difficult to analyze. To overcome this problem, a second lysate was made from cells containing the BmKSL2 vector. These cells were lysed, but only sonicated for 25 seconds, which was long enough to decrease the viscosity but short enough to still have DNA that is visible on a standard agarose gel. After sonication, the lysate was processed according to standard procedures described above and used in the assay “DNA lysate” described herein.

Silica Based Purification:

Binding to silica (0.5 ml) was performed by mixing 0.5 ml lysate (either SP74C or SP2M2) with 0.25 ml DNA lysate and 50 μl Tris (1 M, pH 9) and 9 ml H₂O was added. As a control, the binding to silica of the DNA lysate was investigated. The binding was performed with slow shaking for two hours. For each specific lysate, the binding was performed in three identical samples, while varying number of washing in 1 ml buffer (20 mM Tris, pH 7.3 and 20 mM NaCl) supplemented with 0.02% Tween 20. Each sample was analyzed by agarose gel electrophoresis (FIG. 7A) and by SDS-PAGE gel electrophoresis (FIG. 7B).

Results:

As observed in FIGS. 7A and B, the amount of DNA associated to silica is decreased after each washing but the amount of bound protein is stable. This example shows that the fusion polypeptides SP74C and SP2M2 with a SL2-tag can be purified on silica and that DNA binding is very low under the low salt conditions employed.

Summary of Results from Examples 3-6

As shown in Examples 3-6 several different proteins can be purified using silica with the use of the SL2-tag and the LSL-tag. In all these examples the concentration of salt has been kept low (10-20 mM). The reason for this is that with higher salt concentrations the background binding of other proteins increases. The problem with background binding of other proteins to silica cannot be solved by increasing the number of washings. Most likely, the binding to silica occurs as a two-step reaction in which the initial binding is enhanced by the silica tag but once a protein associates with the silica particle, it deforms and starts to bind to the silica particle via other parts of the protein molecule (Mathé et al (2013) PLoS ONE 8(11): e81346). The secondary binding to silica of the proteins disclosed cannot easily be reversed. For example, the number of washings has little effect on the amount of protein bound by the silica particle. Neither the target protein nor background binding proteins from the E. coli lysate was significantly affected by the number of washings. Importantly, it is still possible to directly use the silica with bound proteins for immunization.

Example 7 Purification of Fragments and Fusion Polypeptides on Q-Sepharose Columns

In order to obtain soluble proteins that can be associated with silica or used with other adjuvants, the antigens with SL2-tag were purified by ion exchange chromatography using Q-sepharose. Additionally, His-tagged antigens purified on Talon columns were used as controls. Purifications were performed according to the following:

Protein Purification on Talon:

Premade columns with 1 ml Talon (GE Healthcare) were used. All proteins were purified according to the description below (step 1-11). The columns were reused but only the same protein was purified on each column.

1. The column was washed with 10 ml TN0.4 buffer (10 mM Tris Ph 7.1, 0.4 M NaCl).

2. 10-15 ml lysate was applied two times on the column.

3. The column was washed with 2×5-10 ml TN0.4 buffer.

4. Sometimes an extra washing step with 5 ml 5 mM Imidazole i TN 0.4 buffer was applied.

5. The recombinant protein was eluted with 0.1 M Imidazole i TN 0.4 buffer.

6. The column was wash with 5 ml 8 M UREA.

7. The column was regenerated with 10 ml MES (20 mM)+NaCl (0.4 M).

8. The column was washed with 20 ml H₂O and saved for the next purification of the same protein.

9. The eluted protein samples were dialyzed against PBS (2×5 l).

10. The samples were sterile filtered (0.2 μm).

11. The absorbance was measured and the samples were frozen.

Protein Purification on Q-Sepharose:

M2N—S, SP2C—S, SP4C—S, SP7C—S, SP74C—S and SP2M2-S were purified according to the description below: Step 1-2 were the same for all purifications:

1. The column was packed with med 4 ml Q-sepharose (GE Healthcare).

2. The column was washed with 10 ml H₂O.

Protein Purification of M2N—S:

3. The column was washed with 2×10 ml TN0.05 (Tris 20 mM pH 7.1 and NaCl 0.05 M).

4. 10 ml M2N—S lysate was mixed with 10 ml H₂O and applied to the column two times.

5. The column was washed with 2×10 ml TN0.05.

6. The column was washed with 5-10 ml TN0.1 (Tris 20 mM pH 7.1 and NaCl 0.1 M).

7. The column was washed with 5-10 ml TN0.15 (Tris 20 mM pH 7.1 and NaCl 0.15 M).

8. The recombinant protein was eluted with 2×5 ml TN0.2 (Tris 20 mM pH 7.1 and NaCl 0.2 M).

9. The eluate was diluted to 30 ml with H₂O.

10. The diluted eluate was added to a new column which was washed and the recombinant protein eluted as described above.

11. The eluted sample was diluted with H₂O to 0.15 M NaCl and sterile filtered (0.2 μM).

12. The absorbance was measured and the samples were frozen.

Purification of SP2C—S:

3. The column was washed with 2×10 ml TN0.1 (Tris 20 mM pH 7.1 and NaCl 0.1 M).

4. 10 ml SP2C—S lysate was mixed with 10 ml H₂O and 0.4 ml NaCl (5 M).

5. The sample was applied on the column two times.

6. The column was washed with 15 ml TN0.2.

7. The column was washed with 5 ml TN0.25.

8. The recombinant protein was eluted with 2×5 ml TN0.3.

9. The eluate (10 ml) was diluted with H₂O to 25 ml and applied on the column two times.

10. The column was washed and the recombinant protein eluted as described above.

11. The eluate was diluted to 20 ml with H₂O and sterile filtered (0.2 μm).

12. The absorbance was measured and the samples were frozen.

Purification of SP4C—S:

3. The column was washed with 2×10 ml TN0.05 (Tris 20 mM pH 7.1 and NaCl 0.05 M).

4. 20 ml SP4C—S lysate was mixed with 20 ml H₂O and applied on the column two times.

5. The column was washed with 2×10 ml TN 0.05.

6. The recombinant protein was eluted with 5 ml TN 0.1.

7. The recombinant protein was eluted with 2×4 ml TN 0.15.

8. The eluates were pooled and 30 ml H₂O was added.

9. The eluate was applied to a new column two times.

10. The column was washed with 2×10 ml TN0.05.

11. The column was washed with 5 ml TN0.1.

12. The recombinant protein was eluted with 3×4 ml TN0.15.

13. The eluate was sterile filtered (0.2 μm).

14. The absorbance was measured and the samples were frozen.

Purification of SP7C—S:

3. The column was washed with 2×10 ml TN0.05 (Tris 20 mM pH 7.1 and NaCl 0.05 M).

4. 20 ml SP7C—S lysate was mixed with 20 ml H₂O and applied on the column two times.

5. The column was washed with 2×10 ml TN 0.05.

6. The recombinant protein was eluted with 5 ml TN 0.1.

7. The recombinant protein was eluted with 3×4 ml TN0.2.

8. The eluates was pooled and 30 ml H₂O was added.

9. The eluate was applied to a new column two times.

10. The column was washed and the recombinant protein eluted as described above.

11. The eluate was pooled and sterile filtered (0.2 μm).

12. The absorbance was measured and the samples were frozen.

Purification of SP74C—S:

3. The column was washed with 2×10 ml TN0.05 (Tris 20 mM pH 7.1 and NaCl 0.05 M).

4. 10 ml SP74C—S lysate was mixed with 10 ml H₂O and applied on the column two times.

5. The column was washed with 10 ml TN0.05.

6. The column was washed with 2×10 ml TN0.1.

7. The recombinant protein was eluted with 2×5 ml TN0.2.

8. The eluate was diluted to 40 ml using H₂O.

9. The eluate was applied to a new column two times.

10. The column was washed and the recombinant protein eluted as described above.

11. The eluate was pooled and sterile filtered (0.2 μm).

12. The absorbance was measured and the samples were frozen.

Purification of SP2M2-S:

3. The column was washed with 2×10 ml TN0.05 (Tris 20 mM pH 7.1 and NaCl 0.05 M).

4. 10 ml SP2M2-S lysate was mixed with 10 ml H₂O and applied on the column two times.

5. The column was washed with 3×10 ml TN0.2 (pH 8).

6. The column was washed with 10 ml TN0.25 (pH 8).

7 The column was washed with 10 ml TN0.3 (pH 8).

8. The recombinant protein was eluted with 10 ml TN0.35 (pH 8).

9. The eluate was diluted to 20 ml with H₂O and applied on the column two times.

10. The column was washed and the recombinant protein eluted as described above.

11. The eluate was pooled and sterile filtered (0.2 μm).

12. The absorbance was measured and the samples were frozen.

As can be seen in FIG. 8, the purity of the SL2-tagged Q-sepharose purified proteins as estimated using SDS-PAGE gel is similar to the purity of His-tagged proteins purified on Talon. The SL2-tag is 22 amino acids long, thus these proteins are slightly larger than the corresponding protein with His-tag.

Example 8 Stability of Purified Antigens

The stability of Q-sepharose purified antigens obtained in Example 7 was tested. The antigens M2N—S, SP2C—S, SP4C—S and SP7C—S were mixed and aliquots were incubated at 37° C., room temperature (RT) and frozen (−20° C.) as a control. After 43 days at 37° C. the antigens exhibited a high level of stability (FIG. 9).

Example 9 Stability of Fusion Antigens

Several different combination of fusion polypeptides have been made using M2N, SP2C, SP4C and SP7C, for example corresponding to SEQ ID NO:34-35 and SEQ ID NO; 92-95. Additionally, fusion proteins comprising three immunogenic fragments are contemplated, such as SP274C (SEQ ID NO:107) SP742C (SEQ ID NO:108).

SP2M2 (SEQ ID NO:34) and SP74C (SEQ ID NO:35) described in Example 6 were selected for further study. Both fusion polypeptide were cloned in the BmKSL2 vector and thus contains the SL2-tag resulting in SP2M2-S(SEQ ID NO:36) and SP74C—S(SEQ ID NO:37). These fusion polypeptides were purified on silica and analyzed by SDS-PAGE gel electrophoresis (FIG. 10). The fusion polypeptides were also purified on Q-sepharose as described in Example 8 and analyzed by SDS-PAGE gel electrophoresis (FIG. 10A). The stability of the fusion polypeptides after purification on Q-sepharose was also tested. The two fusion polypeptides were mixed and one aliquot of the mix was frozen and the other was incubated at 37° C. FIG. 10B shows an SDS-PAGE analysis of the mixed fusion polypeptides after 5 days at −20° C. compared to 5 days at 37° C. Both fusion polypeptides exhibited good stability.

Example 10 Immunological Response in Mice Against SP2C—S, SP4C—S, SP7C—S, and M2N—S

In this Example the four antigens SP2C—S, SP4C—S, SP7C-2, and M2N—S were injected into mice and the antibody responses thereto were investigated.

Material and Method:

Immunization:

Forty two mice (BalbC, weight 18-22 g) were divided into 14 groups with three animals in each group. Procedures were performed on the days as indicated in the Table below; on days 0, 14, 21 and 28 the mice were immunized with a mixture of antigens by injection of 25 μl intra muscularly. Blood samples were collected from the tail vein on days 0, 14, 21, 28 and 35, prior to immunizations. Sera was prepared by allowing the blood to clot and the sera after centrifugation was transferred to a new tube stored at −20° C.

TABLE 3 Overview of immunization procedure. Day Procedure 0 collection of serum samples, immunization 14 collection of serum samples, immunization 28 collection of serum samples, immunization 35 collection of serum samples

The 42 animals were immunized with a mixture containing the four antigens (SP2C—S, SP4C—S, SP7C-2, and M2N—S, corresponding to SEQ ID NO:24, 26, 28 and 21, respectively) with either 3.6 μg of each antigen or 0.36 μg of each antigen. Different amounts of silica beads were used; 2, 6 or 13 μl per dose containing 25 μl and two different sizes of silica beads were used, 7 nm or 0.2-0.3 μm. In group 13, silica beads were replaced by 4 μg per dose of MatrixM/Abisco 100 (Isconova AB, Sweden), and in group 14 no adjuvant was used.

TABLE 4 Summary of the content of vaccines in the different test groups. Antigen amount Adjuvant Group (ng per dose in (silica particle size; number 25 μl) amount per dose in 25 μl) 1 3600 7 nm; 2 μl 2 3600 7 nm; 6 μl 3 3600  7 nm; 13 μl 4 3600 200 nm; 2 μl  5 3600 200 nm; 6 μl  6 3600 200 nm; 13 μl  7 360 7 nm; 2 μl 8 360 7 nm; 6 μl 9 360  7 nm; 13 μl 10 360 200 nm; 2 μl  11 360 200 nm; 6 μl  12 360 200 nm; 13 μl  13 360 Matrix M/Abisco 100 14 360 nil

Analysis of Serum Samples:

Serum samples were analyzed for immune response against the different antigens using a conventional ELISA procedure as described below.

-   -   1. Coating: Microtiter plates (Nunc), were coated separately         with one of SP2C—S, SP4C—S, SP7C-2 and M2N—S dissolved in PBS         (Phosphate buffered Saline) pH 7 at 4 μg/ml. 100 μl was added to         each well in 96-well plate. Coating was performed overnight at         room temperature, 20° C.-25° C.     -   2. Blocking: 100 μl bovine serum albumin (BSA) (Sigma) at a         concentration of 2% in PBS was added to each well and left at         37° C. for 1 hour. Next, wells were washed 4-5 times in PBST         (PBS supplemented with 0.05% Tween20). The plates were not         allowed to dry.     -   3. Next serum samples obtained from immunized mice were added to         the wells. 200 μl PBST was added to the first well and 100 μl to         the rest of the wells. 5 μl of sample was to the first well         resulting in a 40-fold dilution and 100 μl were transferred from         first well to the next and mixed, resulting in a 2-fold         dilution. 2-fold dilutions were continued in the same manner to         the second last well and the last 100 μl were discarded. The         last wells were left without antibodies and used as negative         controls. The samples were incubated for 2 hours 37° C. and then         wash 4-5 times with PBST.     -   4. In order to detect antibody binding anti-mouse-IgG antibodies         (raised in rabbit) conjugated with HRP (Dako) diluted 3000× were         added. The samples were incubated for 1 hour at 37° C. and         thereafter washed 4-5 times with PBST.     -   5. Detection of anti-mouse antibodies was performed as follows:         100 μl OPD substrate, prepared according to manufacturer's         recommendation (Dako), was added per well and incubated for 14         minutes. The reaction was terminated by adding 100 μl 0.5 mol/L         H₂SO₄ and the plates were read in an ELISA spectrophotometer at         495 nm.     -   6. Data was transferred to an Excel worksheet and the absorbance         at 495 nm (A495) was plotted as a function of serum dilution. A         horizontal line was draws through A495=1.5 and the log value of         the dilution for each serum sample where the titration curve         cuts the A495=1.5 line was determined. Mean values and standard         errors for each group of mice sera were calculated.

Results:

ELISA values on days 0 and 35 were plotted for the four separate antigens and shown in FIGS. 11A-D. Average (n=3) and standard errors are shown. All four antigens elicited an antibody response in mice at both concentrations used (360 or 3600 ng per dose). The use of silica beads resulted in a better immune response as compared with antigen being used without adjuvant. This is particularly noticeable for the three antigens SP2C, SP4S and SP7S. It can further be noted that the size of the silica beads (7 or 200 nm) does not seem to be of importance for the elicited antibody response. Within the range used, 2-13 μl per dose, no dose effect was observed. This implies that the use of the lowest amount (2 μl) of silica beads in a dose of 25 μl is sufficient to result in adjuvanticity.

Example 11 Immunological Response in Piglets Against SP2M2-S and SP74C—S

In this Example we assess the IgG serum levels in piglets following an initial immunization with Streptococcus suis fusion antigens SP2M2-S(SEQ ID NO:36) and SP74C—S(SEQ ID NO:37) and the response following a booster immunization, compared with a placebo. The test material, study setup, analysis and results are described.

Material and Methods

Test Animals:

Details on the animals used in this study are given in Table 5 below and the inclusion criteria, exclusion criteria and post inclusion withdrawal criteria applied were the same as in Example 12.

TABLE 5 Detail on animals used in the study. Animal details Sows Piglets Species Porcine Porcine Breed Yorkshire - Landrace Yorkshire - Landrace Sex Female Female/Male Other Stage of gestation: 106 Age: Approximately 4 days gestation on days of age on Day 0 arrival (±1 day) Body weight — ≥1.0 kg on Day 0 Number 3 26 piglets Source Commercial pig farm - Commercial pig farm - (Millerhill, UK) (Millerhill, UK) Fate of animals All study animals will be All study animals will be euthanized and euthanized and incinerated. incinerated.

Allocation/randomization was performed according to the following. On day 0, suitable piglets in each litter were blocked into groups of three (based on descending body weight) and allocated to one of three groups such that within each block of three, one piglet was allocated to each group. For subsequent litters allocation started from where the previous litter's allocation finished. A minimum of eight piglets were required per group. Using a random number generator, each group was then allocated to a study treatment group. No blinding was performed due to the investigative nature of the study.

Test and Control Material:

The test material—was prepared according to Table 6 and the control group received a control dose of placebo, which is selected in order to mimic the test material dose regime. For SP74C—S lot #141118 was used and for SP2M2-S lot #141118 was used.

TABLE 6 Information on test and control material. The formulation comprising SP74C-S (SEQ ID NO: 37) and SP2M2-S (SEQ ID NO: 36) is herein also referred to as “Piggy vaccine”. Test material Study 1 Control Name/Code SP74C-S (SEQ ID Placebo Number NO: 37) and SP2M2-S (SEQ ID NO: 36) Formulation Protein solution in Adjuvant 50 mM Tris pH 7.3 solution in 50 mM Tris pH 7.3 Concentration 40 μg per antigen 100 μg/ml of in 500 μl injection adjuvant volume Storage Conditions +2 to +8° C. +2 to +8° C. Required Method of Intramuscular Intramuscular Administration injection injection Dose Regime Day 0 and 14 Day 0 and 14

Study Design and Procedure:

A summary of the study design is given in Table 7. A total of three pregnant pigs (approximately 1 week before farrowing) were sourced from a commercial pig farm with no history of Streptococcus suis clinical disease. Animals were kept and monitored as described in Example 11.

TABLE 7 Summary of the study design. Treatment No. of Day 0 test Day 14 test Route/ End of Group animals material material volume study day 1 4 Antigen Antigen Intramuscular/ 28 16 μg 16 μg 0.5 ml 4 Antigen Placebo 16 μg

The study was performed as summarized in Table 8. The procedures on day −1, 0, 14 were as described in Example 12. Blood samples were collected from all animals and the body weight of all piglets was recorded on day 0, 7, 14, 21 and 28.

TABLE 8 Summary of the study design. Study day Procedure(s) −3 Farrowing, ear tagging −1 Blood sample 0 Physical examination, body weight, allocation, test material administration  0 (+1 h and +4 h) Clinical observation 7 Blood sample, body weight 14 Blood sample, body weight, test material administration 14 (+1 h and +4 h) Clinical observation 21 Blood sample, body weight 28 Blood sample, body weight Test Material Preparation and Administration

Test Material Preparation:

Test and control material were supplied as ready to use, but were allowed to reach room temperature before administration. The test material was shaken before use.

Test Material Administration:

On day 0 and on day 14, each animal was administered a 0.5 ml volume of the antigen concentration and adjuvant concentration or adjuvant, respectively, according to Tables 6 and 7 by the intramuscular route. All injections were administered to the neck muscle on the right side.

Clinical Observations:

Clinical observation/Injection site reactions post treatment as well as general heath observations were performed as described in Example 12.

Serological Testing:

All samples collected from sows during screening the piglets during the study were analyzed on completion of the study.

Sample Collection and Processing

Blood samples of maximum 2 ml were collected from all piglets on day −1, then again on day 0, 7, 14, 21 and 28. The sample were processed as described in Example 12.

Analysis of Serum Samples:

Serum samples were analyzed for immune response against the SP2M2 and SP74C antigens using the ELISA procedure as described in Example 10, with the following exceptions in steps 1, 3 and 4: Step 1: microtiter plates (Nunc), were coated separately with SP2M2C—S(SEQ ID NO:36), lot #141118), or SP74C—S(SEQ ID NO:37) lot #141118), dissolved in PBS pH 7.3 at 4 μg/ml. 100 μl was added to each well in 96-well plate. Coating was performed overnight at room temperature, 20° C.-25° C. followed by blocking with 100 μl 2% BSA for 1 hour at room temperature; Step 3: after washing of the microtiter wells, serum samples obtained from immunized piglets were added to the wells in serial dilutions and the samples were incubated for 2 hours 37° C. followed by washing 5 times with PBST; and Step 4: in order to detect antibody binding anti-pig-IgG antibodies (Sigma A5670t) conjugated with HRP (Dako) and diluted 10,000× was added. The samples were incubated for 1 hour at 37° C. and then washed 5 times with PBST. Detection of anti-pig antibodies and data analysis were performed as described in step 5 and 6 in Example 9.

Results:

All three sows were negative against the two antigens SP74C—S (SEQ ID NO:37) and SP2M2-S(SEQ ID NO:36) included in the Piggy vaccine when screening samples were applied to a serological test.

The body weight of all piglets increased throughout the observation period as shown in Table 9.

TABLE 9 Body weight of piglets (mean and st. dev. shown). Mean Group Study day weight gain 1 0 7 14 21 28 (kg) Mean 2.30 4.51 6.47 8.44 11.20 8.90 StDev 0.42 1.38 1.93 2.56 3.42 2.73

All animals were successfully administered the test material on days 0 and 14 with no occurrence of mis-dosing and no injection site reactions were observed.

On day 0, one hour post treatment, with the exception of one animal in Group 1 (animal 6164), no abnormal clinical signs were observed in any animal. Animal 6164 was observed to have a lame left hind leg. No pyrexia was observed in any animal, with temperatures ranging between 38.0° C. to 39.9° C. On assessment four hours post treatment, animal 6164 was observed to be lame and depressed with a rectal temperature of 40.2° C. and was diagnosed with suspected abscess upon veterinary examination. No treatment was administered to said animal. No pyrexia was observed in any other study animal, with temperatures ranging between 38.0° C. to 39.7° C.

No abnormal clinical signs were observed in any animal on day 14 post vaccination. No pyrexia was observed in any animal, with temperatures ranging between 38.7° C. to 39.9° C.

FIG. 12 shows that piglets responded against both SP74C—S and SP2M2-S after immunization with “The piggy vaccine”. Initially, a decline of antibody levels is noted from day 0 to day 14, presumably as a result of maternal antibodies obtained via colostrum. A significant enhancement of antibody levels is observed after the second immunization on day 14 (p p<0.001 for SP74C—S and p<0.001 for SP2M2-S)

Thus, this data shows that both SP74C and SP2M2 are able to elicit antigen specific antibody responses after immunisation.

Example 12 Efficacy of a Vaccine Against a Streptococcus suis Challenge in Piglets

In this Example we describe the determination of whether an experimental S. suis vaccine as disclosed herein is effective in the prevention of an artificially induced Streptococcus suis infection in piglets of weaning age. The test material, study setup and analysis of results are described.

Material and Methods

Test Animals:

Details of the animals used in this study are given in Table 10 below.

TABLE 10 Details on animals used in the study. Animal details Sows Piglets Species Porcine Porcine Breed Large white/Landrace Large white/Landrace Sex Female Female/Male Other Stage of gestation: Age: Between 9 and 10 Approximately 103 days days of age on Day 0. gestation on arrival Body weight — ≥1.0 kg on day 0 Number 3 18 piglets Source Commercial high health Commercial high health status pig farm status pig farm

Inclusion Criteria:

Piglets included in the study were confirmed to be in good general health and weigh more than 1.0 kg on day 0.

Exclusion Criteria:

Any piglets not in good general health or weighing less than 1.0 kg were excluded from the study.

Post Inclusion Withdrawal:

Animals were withdrawn from the study if they were injured or showed clinical signs of illness or disease which either could not be treated or constituted a welfare issue. Any animal that showed unacceptable abnormal health following vaccination was euthanized.

Allocation/Randomization:

On day 0, randomization of the group order in each block was carried out using a random number generator.

TABLE 11 Information on test and control material. Test material Vaccine Control Name/Code Group 1: SP274C-S Placebo number (SEQ ID NO: 109) Formulation Protein + adjuvant Adjuvant solution in 50 mM solution in 50 mM Tris Tris pH 7.3 pH 7.3 Concentration 40 μg antigen + 50 μg 100 μg/ml of adjuvant adjuvant in 500 μl injection volume Storage +2 to +8° C. +2 to +8° C. conditions required Method of Intramuscular injection Intramuscular injection administration Dose regime Day 0 and Day 10 Day 0 and Day 10

Challenge Material:

Detailed information of the challenge material is given in Table 12 below.

TABLE 12 Challenge information. Name Streptococcus suis, serotype 2 Year of isolation 2011 County of isolation England, UK Clinical history 3 month old pig with nervous system symptoms Method of administration Intranasal Anticipated titer Approximately 1.0 × 10⁹ colony forming units (cfu) total in 5 ml Dosage regime 5 ml on single occasion (Day 27/31)

Study Design and Procedure:

A summary of the study design is given in Table 13. A total of three pregnant sows (approximately 3 weeks before farrowing) were sourced from a commercial pig farm with no history of S. suis clinical disease, and transported to the Contract Research Organization (CRO).

TABLE 13 Summary of the study design. End of Group No. of Test Route/ study number Group animals material volume Challenge day 1 Vaccine 9 SP274C-S, Intra- S. suis Day 40 μg mus- isolate by 34/38 2 Control 9 Adjuvant cular/ intranasal only 0.5 ml route at 1 × 10⁹ cfu total in 5 ml.

Approximately one week before the expected farrowing date, the sows were placed into farrowing crates within temperature controlled accommodation.

The animals were be routinely monitored around the expected farrowing dates to provide assistance where necessary with farrowing. Following farrowing, the number of piglets produced by each sow was recorded along with the sex of each animal and each animal was ear tagged in duplicate. The navels of all animals were also be sprayed with iodine to prevent infection.

The animals were under veterinary care from the start of the study and animal husbandry will follow standard procedures unless otherwise indicated. The study procedure is outlined below and summarized in Table 14.

TABLE 14 A summary of the study design employed. Study day Procedure(s) −10 Farrowing, ear tagging −1 Blood sample 0 Physical examination, body weight, allocation, test material administration, 0 (+1 hr and +4 hr) Clinical observation 7 Blood sample, body weight 14 Blood sample, body weight, test material administration 14 (+1 hr and Clinical observation +4 hr) 21 Blood sample, body weight 27/31 Clinical observation, blood sample, body weight, challenge primer, challenge Day 27/31 (+1 challenge hour) Day 27/31 (4 Clinical observation hours post challenge) Day 28/32-33/37 Clinical observations 2 times a day (minimum) Day 34/38 Clinical observation, body weight, blood sample, necropsy

At parturition, the number and sex of piglets born and whether they were alive, healthy or weak, dead (stillborn) or mummified fetuses were recorded for each animal.

On day −1 (9 days post farrowing) blood samples were collected from all piglets.

On day 0, the animals were examined by a veterinarian to confirm that they were in good health and suitable for inclusion on the study. The animals were then weighed. Piglets were allocated to two groups and each piglet was then vaccinated with the appropriate material by intramuscular injection. Piglets from each sow were allocated to different groups. A clinical observation was carried out on all animals approximately 1 hour and 4 hours post vaccination to ensure that no adverse reactions are present. Due to the prolonged period between farrowing dates, it was deemed necessary to vaccinate the litters at two separate time points to ensure all piglets were approximately 10 days of age on vaccination.

On day 14, the animals were vaccinated a second time by the intramuscular route with the appropriate material and a clinical observation was carried out on all animals approximately 1 hour and 4 hours post vaccination.

On day 27/31, the animals were weighed then challenged by the intranasal route with S. suis. All litters were challenged on the same day to ensure that all study animals received the same concentration of challenge material, hence the two respective study days for challenge (Day 27 or Day 31 depending on time of birth).

A clinical observation was carried out prior to challenge and then approximately 4 hours post challenge.

Further clinical observations were performed twice daily from Day 28/32 to end of study. Additional welfare observations were carried out as and when required depending on the condition of the animals and the progress of the disease.

On day 34/38, a final clinical observation was carried out, the animals were weighed, then euthanized and samples collected for bacteriology and histopathology.

Blood samples were collected from all animals on Day −1, 7, 14, 21, 27/31 and 34/38.

Test Material Preparation and Administration

Test Material Preparation—

Test and control material were supplied as ready to use and shaken before use.

Test Material Administration—

On day 0 and 14 each animal was administered a 0.5 ml volume by the intramuscular route.

Challenge Preparation and Administration

Challenge Preparation:

On day 26/30, a Microbank™ seed stock cryovial containing the challenge isolate was removed from −70° C. storage and placed in a pre-chilled (−70° C.±10° C.) cryoblock which was transported directly to a class 2 microbiological safety cabinet. Two beads were removed from the vial and streaked onto separate 5% sheep blood agar plates. The plates were incubated aerobically overnight for 21 hours 40 minutes at +37° C. (±2° C.). Following incubation, plates were examined and confirmed as having growth consistent with that expected for the isolate. Colonies were removed from each plate and added to 3×3 ml of pre-warmed vegetable peptone broth supplemented with 3% (v/v) horse serum (supplemented VPB) in bijou bottles to a turbidity of 1.5 McFarland turbidity units (McF) (density measured using a Densitometer, BioMerieux). Each 3 ml volume was then added to 97 ml of pre-warmed VPB to give 3×100 ml challenge cultures which were incubated for 4 hours 5 minutes at +37° C. (±2° C.) on an orbital shaker set at 150 rpm. After incubation the turbidity of each culture was recorded (target was between 2.5 and 3.5 McF—actual turbidity was 3.8 McF).

The cultures were be pooled, then 140 ml of the culture was removed and added to 210 ml of VPB to produce challenge material with a target concentration of 2×10⁸ cfu/ml (1×10⁹ cfu total in 5 ml). The challenge material was transported immediately to the animal accommodation for challenge administration. A sample of the challenge material was retained for titration.

Challenge Administration:

On day 27/31, all animals were administered 5 ml of 1% acetic acid by intranasal application (using a syringe), to the left nostril as a challenge primer and 1 hr later administered 5 ml of the S. suis challenge material, at a concentration of approximately 1×10⁹ cfu total in 5 ml by intranasal application (using a syringe and an aerosol adapter) to the left nostril.

Clinical Observations

Clinical Observation/Injection Site Reactions Post Treatment:

A clinical observation was performed on all animals one hour and four hours post test material administration on Days 0 and 14. The observation consisted of an assessment of the demeanor of the animal as well as an assessment of any local injection site reactions. The rectal temperature of the animals will also be measured on each occasion using a calibrated digital thermometer.

The injection site observations consisted of an assessment of the presence of any swelling at the injection site, and if present, an assessment of the type of reaction (hot, painful, firm or soft). Where possible an estimate of the size of the swelling was recorded.

Clinical Observation Post Challenge:

Clinical observations consisted of assessments of demeanor, behavioral/central nervous system changes, lameness and rectal temperature (° C.) according to a scoring system (see Table 15).

TABLE 15 Clinical observations Score Parameter 0 1 2 3 Rectal temp 38.0° C.-39.5° C. >39.5° C.-40.0° C. >40.0° C.-40.9° C. ≥41.0° C. or <38° C. Demeanor Normal Mild Moderate Severe depression depression depression Description Normal Slightly dull Unwilling but Unable to demeanor but active able to rise, rise and mobile staying apart from others Behavioral/CNS Normal Minor Moderate Severe changes changes changes Description Normal Tremors Uncoordinated Fitting, demeanor involuntary muscle movement Mobility None Mild Moderate Severe Description Normal Lameness Unsteady Paralysis locomotion in one limb when walking or walking on front knees, lameness in more than one limb

The individual scores for each clinical symptom were summed during tabulation of data to give the total clinical score for each animal on each observation to assess temporal progression of disease.

Pigs which were recumbent/moribund and/or showing signs of severe distress, were euthanized immediately on humane grounds by a. intravenous/intraperitoneal/intracardiac administration of a lethal dose of Pentobarbitone Sodium BP.

Necropsy:

On Day 34/38 (or as required following early euthanasia on welfare grounds), animals were euthanized by lethal injection. A gross pathological examination of each carcass will be conducted and samples will be collected.

General Health Observations:

The general health of the animals was assessed twice daily by a suitably qualified person from arrival until the end of the study.

Sample Collection and Processing

Pre-Study Blood Sample Collection:

Blood samples were collected from all sows before farrowing. A maximum of 2 ml of blood was collected into a clotted blood tube on each occasion.

Blood samples were collected from all piglets on day −1, then again on day 7, 14, 21, 27/31 and 34/38 and at necropsy. A maximum of 2 ml of blood will be collected into a clotted blood tube on each occasion.

Blood Sample Processing:

The clotted blood samples were allowed to clot by incubating at +37° C. (±2° C.) for between 30 and 45 minutes. Blood samples were centrifuged at 1,400×g (3000 rpm) for 20 minutes and the sera were transferred into duplicate sterile bijous labeled with reference number, sample type, animal number, study day, collection date, aliquot number. Samples will be stored at −20° C. (±10° C.).

Tissue Samples:

At necropsy, the whole brain was removed from each animal using sterile forceps and scalpels and three brain samples were removed from the brain tissue.

One sample was placed in a sterile container for bacteriological assessment. One sample was stored at −70° C. (±10° C.) as an archive sample. The remaining brain tissue was placed in a container along with 10% formal saline for histopathological analysis.

Analysis

Serological Testing:

All samples collected from sows during screening and from the piglets during the study were analyzed on completion of the study.

Measurement of Challenge Concentration:

A 0.1 ml aliquot of the challenge material (pre- and post-challenge administration) was diluted by tenfold serial dilutions in 0.9 ml volumes of peptone water (10⁻¹ to 10⁻⁷). Duplicate 10 μl aliquots of all dilutions were spotted onto the surface of a 5% sheep blood agar plate and incubated aerobically at +37° C. (±2° C.) for 20 to 24 hours. The number of cfu per ml of culture was calculated by multiplying the number of colonies by the relevant dilution factor.

S. suis Culture from Tissue Samples:

The brain samples from each animal were placed in a separate stomacher bag together with 9.0 ml of peptone water to provide a nominal dilution of 10⁻¹ and homogenized for 30 seconds in a Seward “Stomacher 80” set at high speed. The homogenate will be poured into a sterile universal container. A 20 μl aliquot of homogenate was diluted in 180 μl of peptone water in a sterile U-well microtitration plate to give a 10⁻² dilution. This dilution process was repeated until the homogenate was diluted to 10⁻⁷. Duplicate 10 μl aliquots of each homogenate dilution from 10⁻¹ to 10⁻⁷ were placed on the surface of a well dried 5% sheep blood agar plate. After samples are dry the plate were incubated overnight (20 to 24 hours) at 37° C. (±2° C.). Plates were inspected for typical colonies of S. suis. If present, colonies will be counted.

Histopathological Analysis:

Formalin fixed brain samples were processed and examined following standard procedures by a histopathologist.

Statistical Analysis:

Statistical analysis was carried out on the raw data obtained from the study and data is presented with means and standard deviations as appropriate.

Results

Animal Details:

Animal details One piglet was withdrawn from the study on Day 17 due to death from extensive external bruising as a result of being crushed by the dam. Diagnosis was not considered attributable to the Test Material and no further testing was performed.

Observations Associated with Test Material Administration:

Observations were performed as described above and all animals were deemed to be normal for demeanor following both administration timepoints and no injection reaction were observed.

S. suis Challenge Concentration:

S. suis challenge was successfully administered to all animals on Day 27/31 with no incidence of mis-dosing recorded. The concentrations of the pre- and post-challenge material were 2.8×10⁸ cfu/ml and 2.35×10⁸ cfu/ml respectively, giving a mean challenge concentration of 2.58×10⁸ cfu/ml. This equates to a challenge dose of 1.29×10⁹ cfu total per pig (in 5 ml) which was higher than the target dose of 1.00×10⁹ cfu total but well within the ±0.5 log acceptable range.

Clinical Observations Post-Challenge:

The body weight of all piglets increased throughout the observation period. There was a slight variation in total weight gain between groups, with animals in the control group (Group 2) having the lowest overall weight gain, but differences were marginal. The rectal temperature results were similar in both groups prior to challenge.

Post-challenge, the mean rectal temperatures in both groups increased markedly on Day 29/33 am and remained elevated for the rest of the monitoring period (FIG. 14A). Instances of high rectal temperatures generally were associated with or preceded the onset of clinical signs of S. suis infection and subsequent euthanasia. The frequency of abnormal rectal temperature scores (>39.5° C.) at all scheduled post-challenge observations is summarised in Table 16. Post-challenge the occurrence of abnormal scores was highest in control group (Group 2) at 46.2% and lowest in vaccine group (Group 1) at 28.6%.

TABLE 16 Summary of rectal temperature scores post-challenge. Number of Number % Group Number of Abnormal of Normal Abnormal number Group Observations Scores Scores Scores 1 Vaccine 105 30 75 28.6% 2 Control 106 49 57 46.2%

Prior to challenge, the demeanour scores, behavioural/CNS scores and mobility scores for all animals were normal (score=0). Post-challenge, the mean scores began to rise in Group 2 by Day 30/34 (see FIGS. 14B, 15A and 15B. High demeanour scores were generally associated with euthanasia of animals on welfare grounds.

Total clinical scores comprised rectal temperature, demeanour, mobility and behavioural/CNS scores. Full details of total clinical scores are listed in Table 17. Group mean total clinical scores for scheduled observations are summarised in FIG. 16. Prior to challenge, total clinical scores for most animals were normal (score=0) with the exception of sporadic high rectal temperatures in a small number of animals, likely to be stress related. Post-challenge, the mean scores began to rise initially in all groups on Day 29/33. High total clinical scores were generally associated with euthanasia of animals on welfare grounds. Overall, the vaccine group (Group 1) had lower mean scores throughout the monitoring period when compared to the control group (Group 2) (FIG. 16).

TABLE 17 A Total clinical score for vaccine group (Antigen SP274C-S, 40 μg) monitored at morning clinical observation (am) and at afternoon clinical observation (pm). Underscore“_” marks animal euthanized on welfare grounds. Study Day Animal 26/30 27/31 28/32 29/33 30/34 number am am pm am pm am pm am pm 6475 0 0 2 1 0 0 0 0 0 6774 0 0 1 0 0 0 0 0 0 6776 1 0 2 1 0 0 0 2 1 6781 1 0 2 0 0 0 0 0 0 6782 1 0 1 0 0 0 0 0 2 6787 1 0 0 0 0 0 0 0 0 6793 1 0 0 0 0 1 0 1 2 6794 1 0 0 0 0 0 0 0 1 Group Mean 0.75 0.00 1.00 0.25 0.00 0.13 0.00 0.38 0.75 St Dev 0.46 0.00 0.93 0.46 0.00 0.35 0.00 0.74 0.89 Study Day Animal 31/35 32/36 33/37 34/38 number am pm am pm am pm am 6475 0 0 1 0 1 1 0 6774 0 0 1 0 1 0 0 6776 1 0 6 5 6781 1 0 0 0 1 1 1 6782 2 1 0 0 0 1 0 6787 0 0 0 0 1 0 0 6793 1 0 2 0 0 0 1 6794 0 0 1 0 0 0 1 Group Mean 0.63 0.13 1.38 0.63 0.57 0.43 0.43 St Dev 0.74 0.35 2.00 1.77 0.53 0.53 0.53

TABLE 17 B Total clinical score for controls monitored at morning clinical observation (am) and at afternoon clinical observation (pm). Underscore“_” marks animal euthanized on welfare grounds. Study Day Animal 26/30 27/31 28/32 29/33 30/34 number am am pm am pm am pm am pm 6477 0 0 2 0 1 2 2 0 1 6482 1 1 2 1 2 3 2 4 6773 1 0 2 0 0 1 0 0 0 6779 1 0 0 0 0 1 0 2 3 6783 0 0 0 0 0 2 3 1 3 6786 0 0 1 0 0 1 0 0 1 6788 1 1 0 0 0 0 1 0 1 6789 0 0 0 0 0 1 0 0 0 6792 0 0 0 0 0 0 0 0 1 Group Mean 0.44 0.22 0.78 0.11 0.33 1.22 0.89 0.78 1.25 Study Day Animal 31/35 32/36 33/37 34/38 number am pm am pm am pm am 6477 1 4 5 4 3 5 2 6482 6773 0 2 1 2 10 6779 6783 1 0 1 0 0 2 1 6786 0 1 1 0 0 1 1 6788 0 1 0 0 0 0 1 6789 1 0 0 0 1 0 1 6792 0 0 0 0 0 0 0 Group Mean 0.43 1.14 1.14 0.86 2.00 1.33 1.00

A total of 4 animals were euthanized or died prior to scheduled necropsy.

Animals were generally euthanized at early to moderate stages of disease development for welfare reasons.

The first mortality occurred three days post-challenge administration (Study Day 20/34) and animals were withdrawn from study until 6 day post-challenge (Study Day 33/37). Mortalities occurred with 33.3% ( 3/9) mortality rate in the control group (Group 2) and 12.5% in vaccine group (Group 1). All post-challenge mortalities were consistent with S. suis disease (based on clinical signs and/or bacteriology/histopathology).

Recovery of S. suis from Brain Tissue:

Colonies consistent with S. suis were recovered from brain tissue in all animals that were euthanized or died prior to scheduled necropsy (Table 18). No colonies consistent with S. suis were recovered from brain tissue of any animal which survived to scheduled necropsy

TABLE 18 Summary of bacteriology results Number of S. suis Group Number of positive number Group animals animals Mean cfu/g 1 Vaccine 8 1 1.13E+02 2 control 9 3 1.71E+04

Sample Analysis:

Serum samples were analysed for immune response against SP274C—S with standard ELISA method as described in Example 11, wherein plates were coated with the corresponding antigen. Briefly, antigens were used to coat microtiter wells at 4 μg/ml and serum samples at various dilutions were applied. Binding was detected with HRP conjugated anti-swine antibodies. Serum titer is expressed as the log value of the dilution required to result in an A490 value of 1.5. As an example, a titer expressed as 3.3 means that a dilution of 2000 times gives A490=1.5.

Serum titers in sows and average serum titres in piglets are shown in Tables 19 and 20, respectively. Prior to vaccination (Day −1) animals in vaccine group were observed to have mean antibody titre of 2.16 against the SP274C—S antigen (range between 1.45 and 2.65). Following vaccination, seven of the eight animals, had an antibody response to vaccination with the SP274C—S antigen, with a mean antibody titre of 3.14 (see FIG. 17A). In the control group (adjuvant only), animals had antibodies against the antigen, due to maternally derived antibodies. There was a decline in the antibody response of animals in the control group following vaccination (see FIG. 17B.

TABLE 19 Antibody titres in sows included in the study. Animal ID. SP274C-S 66 3.15 376 2.45 966 2.7

TABLE 20 Group mean antibody titres in piglets. SP274C-S Group Day Day number Group −1 27/31 1 vaccine 2.16 3.14 2 control 1.98 1.86

In summary, the animals vaccinated with SP274C—S exhibited a lower added clinical score as compared to the control animals as well as a lower mortality rate (FIG. 19 and Table 17).

Itemized List of Embodiments

-   -   1. An immunogenic polypeptide for use as a medicament, wherein         said polypeptide comprises an amino acid sequence selected from         the group consisting of SEQ ID NO:4 and fragments thereof; SEQ         ID NO:3 and fragments thereof; SEQ ID NO:2 and fragments         thereof; a fragment comprising SEQ ID NO:5, provided the         fragment comprising SEQ ID NO:5 is less than 500 amino acids         long; a fragment comprising SEQ ID NO:6, provided the fragment         comprising SEQ ID NO:6 is less than 500 amino acids long; and         amino acid sequences with at least 80%-identity to any one of         said amino acid sequences, such as an amino acid sequence         selected from the group consisting of SEQ ID NO:2 and fragments         thereof; SEQ ID NO:3 and fragments thereof; SEQ ID NO:4 and         fragments thereof; SEQ ID NO:5; SEQ ID NO:38, SEQ ID NO:6; and         amino acid sequences with at least 80%-identity to any one of         said amino acid sequences.     -   2. An immunogenic polypeptide for use in the prophylactic         treatment of a Streptococcus suis infection, wherein said         immunogenic polypeptide comprises an amino acid sequence         selected from the group consisting of SEQ ID NO:4 and fragments         thereof; SEQ ID NO:3 and fragments thereof; SEQ ID NO:2 and         fragments thereof; a fragment comprising SEQ ID NO:5, provided         the fragment comprising SEQ ID NO:5 is less than 500 amino acids         long; a fragment comprising SEQ ID NO:6, provided the fragment         comprising SEQ ID NO:6 is less than 500 amino acids long; and         amino acid sequences with at least 80%-identity to any one of         said amino acid sequence, such as an amino acid sequence         selected from the group consisting of SEQ ID NO:4 and fragments         thereof; SEQ ID NO:3 and fragments thereof; SEQ ID NO:2 and         fragments thereof; SEQ ID NO:5; SEQ ID NO:38, SEQ ID NO:6; and         amino acid sequences with at least 80%-identity to any one of         said amino acid sequences.     -   3. Immunogenic polypeptide for use according to item 1 or 2,         wherein said immunogenic polypeptide comprises an amino acid         sequence selected from the group consisting of SEQ ID NO:4 and         fragments thereof; SEQ ID NO:3 and fragments thereof; SEQ ID         NO:2 and fragments thereof; a fragment comprising SEQ ID NO:5,         provided the fragment comprising SEQ ID NO:5 is less than 500         amino acids long; and amino acid sequences with at least         80%-identity to any one of said amino acid sequences, such as an         amino acid sequence selected from the group consisting of SEQ ID         NO:4 and fragments thereof; SEQ ID NO:3 and fragments thereof;         SEQ ID NO:2 and fragments thereof; SEQ ID NO:5; SEQ ID NO:38 and         amino acid sequences with at least 80%-identity to any one of         said amino acid sequences, such as an amino acid sequence         selected from the group consisting of SEQ ID NO:4 and fragments         thereof; SEQ ID NO:3 and fragments thereof; SEQ ID NO:2 and         fragments thereof; and amino acid sequences with at least         80%-identity to any one of said amino acid sequences.     -   4. Immunogenic polypeptide for use according to any one of items         1-3, wherein said amino acid sequence is selected from the group         consisting of fragments of SEQ ID NO:4, fragments of SEQ ID         NO:3, fragments of SEQ ID NO:2, a fragment comprising SEQ ID         NO:5, provided the fragment comprising SEQ ID NO:5 is less than         500 amino acids long and amino acid sequences with at least         80%-identity to any one of said fragments, such as an amino acid         sequence selected from the group consisting of fragments of SEQ         ID NO:4, fragments of SEQ ID NO:3, fragments of SEQ ID NO:2, SEQ         ID NO:5, SEQ ID NO:38 and amino acid sequences with at least         80%-identity to any one of said fragments.     -   5. Immunogenic polypeptide for use according to any one of items         1-4, wherein said fragment is approximately 100-500 amino acids         long, such as approximately 200-500 amino acids long, such as         approximately 250-450 amino acids long.     -   6. Immunogenic polypeptide for use according to any one of items         1-5, wherein said fragment is an N-terminal or a C-terminal         fragment.     -   7. Immunogenic polypeptide for use according to any one of items         1-6, wherein said fragment is selected from the group consisting         of fragments comprising SEQ ID NO:7 or SEQ ID NO:8; fragments         comprising SEQ ID NO:9 or SEQ ID NO:10; fragments comprising SEQ         ID NO:11 or SEQ ID NO:12; a fragment comprising SEQ ID NO:5,         provided the fragment comprising SEQ ID NO:5 is less than 500         amino acids long; a fragment comprising SEQ ID NO:6, provided         the fragment comprising SEQ ID NO:6 is less than 500 amino acids         long; and amino acid sequences with at least 80%-identity to any         one of said fragments, such as a fragment selected from the         group consisting of fragments comprising SEQ ID NO:7 or SEQ ID         NO:8; fragments comprising SEQ ID NO:9 or SEQ ID NO:10;         fragments comprising SEQ ID NO:11 or SEQ ID NO:12; SEQ ID NO:5         or SEQ ID NO:38 (M2long); and amino acid sequences with at least         80%-identity to any one of said fragments, such as a fragment         selected from the group consisting of fragments comprising SEQ         ID NO:7 or SEQ ID NO:8; fragments comprising SEQ ID NO:10;         fragments comprising SEQ ID NO:12; SEQ ID NO:5; and amino acid         sequences with at least 80%-identity to any one of said         fragments.     -   8. Immunogenic polypeptide for use according to any one of items         1-7, wherein said fragment is selected from the group consisting         of fragments comprising SEQ ID NO:8; fragments comprising SEQ ID         NO:10; fragments comprising SEQ ID NO:12; SEQ ID NO:5; and amino         acid sequences with at least 80%-identity to any one of said         fragments.     -   9. Immunogenic polypeptide for use according to any one of items         1-8, wherein said fragment further comprises additional amino         acid residues at the N- and/or C-terminus.     -   10. Immunogenic polypeptide for use according to item 9, wherein         said fragment comprises a methionine residue at the N-terminus.     -   11. Immunogenic polypeptide for use according to any one of the         preceding items, further comprising an amino acid sequence         capable of binding to silica.     -   12. Immunogenic polypeptide for the use according to item 11,         wherein said amino acid sequence capable of binding to silica is         selected from SEQ ID NO:32 and SEQ ID NO:33 and amino acids         sequences with at least 80%-identity to SEQ ID NO:32 or SEQ ID         NO:33, such as wherein said amino acid sequence capable of         binding to silica is SEQ ID NO:32 or SEQ ID NO:33.     -   13. Immunogenic polypeptide fragment, comprising an amino acid         sequence selected from         -   i) an amino acid sequence selected the group consisting of             SEQ ID NO: 7, SEQ ID NO:8, SEQ ID NO:9, SEQ ID NO:10, SEQ ID             NO:11 and SEQ ID NO:12, and         -   ii) an amino acid sequence with at least 80%-identity to an             amino acid sequence defined in i).     -   14. Immunogenic polypeptide fragment, comprising an amino acid         sequence selected from         -   iii) an amino acid sequence selected the group consisting of             SEQ ID NO:5; SEQ ID NO:38, SEQ ID NO:6, SEQ ID NO:7, SEQ ID             NO:8, SEQ ID NO:9, SEQ ID NO:10, SEQ ID NO:11 and SEQ ID             NO:12, and         -   iv) an amino acid sequence with at least 80%-identity to an             amino acid sequence defined in iii), for use in the             prophylactic treatment of a Streptococcus suis infection.     -   15. Immunogenic polypeptide fragment according to item 14,         wherein the sequence iii) is selected from the group consisting         of SEQ ID NO:5, SEQ ID NO:38, SEQ ID NO:8, SEQ ID NO:10 and SEQ         ID NO:12, such as the group consisting of SEQ ID NO:5, SEQ ID         NO:8, SEQ ID NO:10 and SEQ ID NO:12.     -   16. Immunogenic polypeptide fragment according to item 13 or 15,         wherein the sequence i) or iii) is selected from the group         consisting of SEQ ID NO:8, SEQ ID NO:10 and SEQ ID NO:12, such         as the group consisting of SEQ ID NO:10 and SEQ ID NO:12, such         as the group consisting of SEQ ID NO:8 and SEQ ID NO:12, such as         the group consisting of SEQ ID NO:8 and SEQ ID NO:10.     -   17. Fusion polypeptide comprising         -   a) a first immunogenic polypeptide unit, and         -   b) a second immunogenic polypeptide unit,         -   wherein at least one of said first and second immunogenic             polypeptide units is an immunogenic polypeptide fragment             selected from the group consisting of fragments of SEQ ID             NO:4; fragments of SEQ ID NO:3; fragments comprising SEQ ID             NO:2; a fragment comprising SEQ ID NO:5, provided the             fragment comprising SEQ ID NO:5 is less than 500 amino acids             long; a fragment comprising SEQ ID NO:6, provided the             fragment comprising SEQ ID NO:6 is less than 500 amino acids             long; and amino acid sequences with at least 80%-identity to             any one of said fragments,         -   such as the group consisting of fragments of SEQ ID NO:4;             fragments of SEQ ID NO:3; fragments of SEQ ID NO:2; SEQ ID             NO:5; SEQ ID NO:38; SEQ ID NO:6, and amino acid sequences             with at least 80%-identity to any one of said fragments,             provided that said first and said second immunogenic             polypeptide units are from different native proteins.     -   18. Fusion polypeptide according to item 17,         -   wherein said first and second immunogenic polypeptide units             are immunogenic polypeptide fragments selected from the             group consisting of fragments of SEQ ID NO:4; fragments of             SEQ ID NO:3; fragments comprising SEQ ID NO:2; a fragment             comprising SEQ ID NO:5, provided the fragment comprising SEQ             ID NO:5 is less than 500 amino acids long; a fragment             comprising SEQ ID NO:6, provided the fragment comprising SEQ             ID NO:6 is less than 500 amino acids long; and amino acid             sequences with at least 80%-identity to any one of said             fragments,         -   such as the group consisting of fragments of SEQ ID NO:4;             fragments of SEQ ID NO:3; fragments of SEQ ID NO:2; SEQ ID             NO:5; SEQ ID NO:38; SEQ ID NO:6, and amino acid sequences             with at least 80%-identity to any one of said fragments,         -   provided that said first and said second immunogenic             polypeptide units are from different native proteins.     -   19. Fusion polypeptide according to item 18, wherein said first         and second immunogenic polypeptide units are immunogenic         polypeptide fragments selected from the group consisting of         fragments of SEQ ID NO:4; fragments of SEQ ID NO:3; fragments of         SEQ ID NO:2; SEQ ID NO:5; and SEQ ID NO:38, and amino acid         sequences with at least 80%-identity to any one of said         fragments.     -   20. Fusion polypeptide according to any one of items 17-19,         wherein each of the first and second immunogenic polypeptide         unit independently is approximately 100-500 amino acids long,         such as approximately 200-500 amino acids long, such as         approximately 250-450 amino acids long.     -   21. Fusion polypeptide according to any one of items 17-20,         wherein said first and second immunogenic polypeptide units are         selected from the group consisting of fragments comprising SEQ         ID NO:7 or SEQ ID NO:8; fragments comprising SEQ ID NO:9 or SEQ         ID NO:10; fragments comprising SEQ ID NO:11 or SEQ ID NO:12; a         fragment comprising SEQ ID NO:5, provided the fragment         comprising SEQ ID NO:5 is less than 500 amino acids long and), a         fragment comprising SEQ ID NO:6, provided the fragment         comprising SEQ ID NO:6 is less than 500 amino acids long; and         amino acid sequences with at least 80%-identity to any one of         said fragments; such as the group consisting of fragments         comprising SEQ ID NO:8; fragments comprising SEQ ID NO:10;         fragments comprising SEQ ID NO:12; a fragment comprising SEQ ID         NO:5, provided the fragment comprising SEQ ID NO:5 is less than         500 amino acids long; and amino acid sequences with at least         80%-identity to any one of said fragments.     -   22. Fusion polypeptide according to any one of items 17-21,         wherein first and second immunogenic polypeptide units are         selected from the group consisting of fragments SEQ ID NO:5, SEQ         ID NO:38, SEQ ID NO:6, SEQ ID NO:7, SEQ ID NO:8, SEQ ID NO:9,         SEQ ID NO:10, SEQ ID NO:11 and SEQ ID NO:12, and amino acid         sequences with at least 80%-identity to any one of said         fragments; such as the group consisting of fragments SEQ ID         NO:5, SEQ ID NO:38, SEQ ID NO:8, SEQ ID NO:10, and SEQ ID NO:12,         and amino acid sequences with at least 80%-identity to any one         of said fragments, such as the group consisting of fragments SEQ         ID NO:8, SEQ ID NO:10, and SEQ ID NO:12, and amino acid         sequences with at least 80%-identity to any one of said         fragments.     -   23. Fusion polypeptide according to any one of items 17-22,         wherein said fusion polypeptide is selected from the group         consisting of fusion polypeptides comprising SEQ ID NO:10 and         SEQ ID NO:8; fusion polypeptides comprising SEQ ID NO:5 and SEQ         ID NO:12; fusion polypeptides comprising SEQ ID NO:5 or SEQ ID         NO:38 and SEQ ID NO:10; fusion polypeptides comprising SEQ ID         NO:8 and SEQ ID NO:12; fusion polypeptides comprising SEQ ID         NO:8 and SEQ ID NO:5 or SEQ ID NO:38; and fusion polypeptides         comprising SEQ ID NO:12 and SEQ ID NO:10,         -   such as the group consisting of fusion polypeptides             comprising SEQ ID NO:10 and SEQ ID NO:8; fusion polypeptides             comprising SEQ ID NO:8 and SEQ ID NO:5 or SEQ ID NO:38; and             fusion polypeptides comprising SEQ ID NO:12 and SEQ ID             NO:10,         -   such as the group consisting of fusion polypeptides             comprising SEQ ID NO:8 and SEQ ID NO:5; and fusion             polypeptides comprising SEQ ID NO:12 and SEQ ID NO:10.     -   24. Fusion polypeptide according to any one of items 17-23,         wherein said fusion polypeptide comprises an amino acid sequence         selected from the group consisting of SEQ ID NO:92, SEQ ID         NO:93, SEQ ID NO:94, SEQ ID NO:95, SEQ ID NO:96, SEQ ID NO:34,         SEQ ID NO:35 and any of said fusion polypeptides wherein at         least one of said units exhibits at least 80%-identity to any         one of SEQ ID NO:8, SEQ ID NO:10, SEQ ID NO:12 or SEQ ID NO:5.     -   25. Fusion polypeptide according to any one of items 17-24,         wherein said fusion polypeptide comprises an amino acid sequence         selected from the group consisting of SEQ ID NO:34; SEQ ID         NO:35; SEQ ID NO:92 and any fusion polypeptide wherein at least         one of said units exhibits at least 80%-identity to any one of         SEQ ID NO:8, SEQ ID NO:10, SEQ ID NO:12 and SEQ ID NO:5, such as         the group consisting SEQ ID NO:34; SEQ ID NO:35, and any fusion         polypeptide wherein at least one of said units exhibits at least         80%-identity to any one of SEQ ID NO:8, SEQ ID NO:10, SEQ ID         NO:12 and SEQ ID NO:5.     -   26. Fusion polypeptide according to any one of items 17-25,         wherein said fusion polypeptide is SEQ ID NO:34 or SEQ ID NO:35,         or a fusion polypeptide wherein at least one of said units         exhibits at least 80%-identity to any one of SEQ ID NO:8, SEQ ID         NO:10, SEQ ID NO:12 and SEQ ID NO:5.     -   27. Fusion polypeptide according to any one of items 17-26         comprising three or four of the immunogenic polypeptide         fragments as defined in any one of items 13-16.     -   28. Fusion polypeptide according to item 27, comprising an amino         acid sequence selected from the group consisting SEQ ID NO:8,         SEQ ID NO:10, SEQ ID NO:12 and amino acid sequences which         exhibit at least 80%-identity to any one of SEQ ID NO:8, SEQ ID         NO:10 and SEQ ID NO:12.     -   29. Fusion polypeptide according to item 28, comprising an         immunogenic polypeptide fragment with at least 80%-identity with         SEQ ID NO:8, an immunogenic polypeptide fragment with at least         80%-identity with SEQ ID NO:10 and an immunogenic polypeptide         fragment with at least 80%-identity with SEQ ID NO:12,         preferably comprising an immunogenic polypeptide fragment with         100%-identity with SEQ ID NO:8, an immunogenic polypeptide         fragment with 100%-identity with SEQ ID NO:10 and an immunogenic         polypeptide fragment with 100%-identity with SEQ ID NO:12.     -   30. Fusion polypeptide according to item 28 or 29, comprising         SEQ ID NO:8, SEQ ID NO:10 and SEQ ID NO:12.     -   31. Fusion polypeptide according to item 29, comprising SEQ ID         NO:107 or SEQ ID NO:108 or a amino acid sequence which exhibits         at least 80%-identity to SEQ ID NO:107 or SEQ ID NO:108.     -   32. Fusion polypeptide according to item 30 or 31, selected from         the group consisting of SEQ ID NO:107, 108, 109 and 110.     -   33. Fusion polypeptide according to any one of items 17-32,         further comprising a linker.     -   34. Immunogenic polypeptide fragment according to any one of         items 13-16 or fusion polypeptide according to any one of items         17-33, wherein said fragment or fusion polypeptide further         comprises additional amino acid residues at the N- and/or         C-terminus.     -   35. Immunogenic polypeptide fragment or fusion polypeptide         according to item 34 further comprising a methionine residue at         the N-terminus.     -   36. Immunogenic polypeptide fragment according to any one of         items 13-16 and 34-35 or fusion polypeptide according to any one         of items 17-35, further comprising an additional amino acid         sequence capable of binding to silica.     -   37. Immunogenic polypeptide fragment or fusion polypeptide         according to item 36, wherein said amino acid sequence capable         of binding to silica is selected from SEQ ID NO:32, SEQ ID NO:33         and amino acids sequences with at least 80%-identity to SEQ ID         NO:32 or SEQ ID NO:33, such as wherein said amino acid sequence         capable of binding to silica is SEQ ID NO:32 or SEQ ID NO:33.     -   38. Immunogenic polypeptide fragment or fusion polypeptide         according to any one of items 13, 15-37 for use as a medicament.     -   39. Immunogenic polypeptide fragment or fusion polypeptide         according to item 38 for use in the prophylactic treatment of a         Streptococcus suis infection.     -   40. Polynucleotide encoding an immunogenic polypeptide, an         immunogenic polypeptide fragment or a fusion protein as defined         in any one of items 1-39.     -   41. Expression vector comprising a polynucleotide according to         item 40.     -   42. Host cell comprising an expression vector according to item         41.     -   43. Method of producing an immunogenic polypeptide, an         immunogenic polypeptide fragment or a fusion protein according         to any one of items 1-39, comprising         -   culturing a host cell according to item 42 under conditions             permissive of expression of said polypeptide from said             expression vector, and         -   isolating said polypeptide.     -   44. Immunogenic composition comprising at least one immunogenic         polypeptide as defined in any one of items 1-12, at least one         immunogenic polypeptide fragment as defined in any one of items         13-16 and 34-39 or at least one fusion polypeptide as defined in         any one of items 17-39.     -   45. Immunogenic composition according to item 44, comprising         one, two, three or four of said immunogenic polypeptides or         immunogenic polypeptide fragments, such as two, three or four of         said immunogenic polypeptides or immunogenic polypeptide         fragments, such as three or four of said immunogenic         polypeptides or immunogenic polypeptide fragments, such as four         of said immunogenic polypeptides or immunogenic polypeptide         fragments.     -   46. Immunogenic composition according to any one of items 44-45,         wherein said at least one immunogenic polypeptide fragment is         provided in fusion with a different at least one different         immunogenic polypeptide fragment to form a fusion polypeptide as         defined in any one of items 17-39.     -   47. Immunogenic composition according to items 46, wherein said         composition comprises a fusion polypeptide as defined in any one         of items 17-39 and optionally one or two immunogenic polypeptide         fragments as defined in any one of items 13-16 and 34-39 not in         the form of a fusion polypeptide.     -   48. Immunogenic composition according to item any one of items         46-47, wherein said composition comprises at a fusion         polypeptide comprising three immunogenic polypeptide fragments         as defined in any one of items 13-16 and 34-39 and optionally         one immunogenic polypeptide fragments as defined in any one of         items 13-16 and 34-39 not in the form of a fusion polypeptide.     -   49. Immunogenic composition according to any one of items 44-48,         selected from the group consisting of immunogenic compositions         comprising the group consisting of         -   a fusion polypeptide comprising SEQ ID NO:10 and SEQ ID NO:8             and at least one polypeptide comprising an amino acid             sequence selected from SEQ ID NO:5, 6, 11 and 12 not in the             form of a fusion polypeptide; a fusion polypeptide             comprising SEQ ID NO:8 and SEQ ID NO:5 and at least one             polypeptide comprising an amino acid sequence selected from             SEQ ID NO:9, 10, 11 and 12 not in the form of a fusion             polypeptide; and         -   a fusion polypeptide comprising SEQ ID NO:12 and SEQ ID             NO:10 and at least one polypeptide comprising an amino acid             sequence selected from SEQ ID NO:5, 6, 7 and 8 not in the             form of a fusion polypeptide; such as the group consisting             of         -   a fusion polypeptide comprising SEQ ID NO:8 and SEQ ID NO:5             and at least one polypeptide comprising an amino acid             sequence selected from SEQ ID NO: 9, 10, 11 and 12 not in             the form of a fusion polypeptide; and a fusion polypeptide             comprising SEQ ID NO:12 and SEQ ID NO:10 and at least one             polypeptide comprising an amino acid sequence selected from             SEQ ID NO:5, 6, 8 and 9 not in the form of a fusion             polypeptide.     -   50. Immunogenic composition according to item 49, selected from         the group consisting of immunogenic compositions comprising         -   a fusion polypeptide comprising SEQ ID NO:10 and SEQ ID NO:8             and at least one polypeptide comprising an amino acid             sequence selected from SEQ ID NO:5 and 12 not in the form of             a fusion polypeptide;         -   a fusion polypeptide comprising SEQ ID NO:8 and SEQ ID NO:5             and at least one polypeptide comprising an amino acid             sequence selected from SEQ ID NO:10 and 12 not in the form             of a fusion polypeptide; and a fusion polypeptide comprising             SEQ ID NO:12 and SEQ ID NO:10 and at least one polypeptide             comprising an amino acid sequence selected from SEQ ID NO:5             and 8 not in the form of a fusion polypeptide; such as the             group consisting of consisting of immunogenic compositions             comprising         -   a fusion polypeptide comprising SEQ ID NO:8 and SEQ ID NO:5             and at least one polypeptide comprising an amino acid             sequence selected from SEQ ID NO:10 and 12 not in the form             of a fusion polypeptide; and a fusion polypeptide comprising             SEQ ID NO:12 and SEQ ID NO:10 and at least one polypeptide             comprising an amino acid sequence selected from SEQ ID NO:5             and 8 not in the form of a fusion polypeptide.     -   51. Immunogenic composition according to item 49 or 50,         comprising two amino acid sequences not in the form of a fusion         polypeptide, provided that said two amino acid sequences are         from different native proteins.     -   52. Immunogenic composition according to any one of items 44-51,         wherein said fusion polypeptide is selected from the group of         fusion polypeptides consisting of fusion polypeptides comprising         SEQ ID NO:92, fusion polypeptides comprising SEQ ID NO:93,         fusion polypeptides comprising SEQ ID NO:94, fusion polypeptides         comprising SEQ ID NO:95, fusion polypeptides comprising SEQ ID         NO:96, fusion polypeptides comprising SEQ ID NO:34, fusion         polypeptides comprising SEQ ID NO:35, and any of said fusion         polypeptides wherein one or both units exhibit at least         80%-identity to any one of SEQ ID NO:8, SEQ ID NO:10, SEQ ID         NO:12 or SEQ ID NO:5, such as the group of fusion polypeptides         consisting of fusion polypeptides comprising SEQ ID NO:92,         fusion polypeptides comprising SEQ ID NO:34 and fusion         polypeptides comprising SEQ ID NO:35 and any of said fusion         polypeptides wherein one or both units exhibit at least         80%-identity to any one of SEQ ID NO:8, SEQ ID NO:10, SEQ ID         NO:12 or SEQ ID NO:5, such as the group of fusion polypeptides         consisting of fusion polypeptides comprising SEQ ID NO:34 and         fusion polypeptides comprising SEQ ID NO:35, and any of said         fusion polypeptides wherein one or both units exhibit at least         80%-identity to any one of SEQ ID NO:8, SEQ ID NO:10, SEQ ID         NO:12 or SEQ ID NO:5.     -   53. Immunogenic composition according to any one of items 44-52,         wherein said immunogenic composition is selected from the group         consisting of immunogenic compositions comprising         -   a fusion polypeptide comprising SEQ ID NO:34 and at least             one polypeptide comprising an amino acid sequence selected             from SEQ ID NO:10 and 12 not in the form of a fusion             polypeptide; and         -   a fusion polypeptide comprising SEQ ID NO:35 and at least             one polypeptide comprising an amino acid sequence selected             from SEQ ID NO:5 and 8 not in the form of a fusion             polypeptide;         -   and any of said fusion polypeptides wherein one or both             units exhibit at least 80%-identity to any one of SEQ ID             NO:8, SEQ ID NO:10, SEQ ID NO:12 or SEQ ID NO:5.     -   54. Immunogenic composition according any one of items 44-53,         comprising one or two fusion polypeptides, such as a fusion         polypeptide comprising SEQ ID NO:34 and a fusion polypeptide         comprising SEQ ID NO:35.     -   55. Immunogenic composition according to item 54, wherein said         composition comprises a fusion polypeptide comprising three or         four immunogenic polypeptide fragments as defined in any one of         items 13-16 and 34-39.     -   56. Immunogenic composition according to item 55, wherein said         composition comprises a fusion polypeptide comprising an amino         acid sequence selected from the group consisting of SEQ ID NO:8,         SEQ ID NO:10, SEQ ID NO:12 and amino acid sequences which         exhibit at least 80%-identity to any one of SEQ ID NO:8, SEQ ID         NO:10 and SEQ ID NO:12.     -   57. Immunogenic composition according to item 56, wherein said         composition comprises a fusion polypeptide comprising an         immunogenic polypeptide fragment with at least 80%-identity with         SEQ ID NO:8, an immunogenic polypeptide fragment with at least         80%-identity with SEQ ID NO:10 and an immunogenic polypeptide         fragment with at least 80%-identity with SEQ ID NO:12,         preferably comprising an immunogenic polypeptide fragment with         100%-identity with SEQ ID NO:8, an immunogenic polypeptide         fragment with 100%-identity with SEQ ID NO:10 and an immunogenic         polypeptide fragment with 100%-identity with SEQ ID NO:12.     -   58. Immunogenic composition according to item 57, wherein said         composition comprises a fusion polypeptide comprising SEQ ID         NO:8, SEQ ID NO:10 and SEQ ID NO:12.     -   59. Immunogenic composition according to item 57, wherein said         composition comprises a fusion polypeptide comprising SEQ ID         NO:107 or SEQ ID NO:108 or an amino acid sequence which exhibits         at least 80%-identity to SEQ ID NO:107 or SEQ ID NO:108.     -   60. Immunogenic composition according to item 58 or 59, wherein         said composition comprises a fusion polypeptide selected from         the group consisting of SEQ ID NO:107, 108, 109 and 110.     -   61. Immunogenic composition according to any one of items 44-60,         wherein said polypeptide are isolated or purified.     -   62. Immunogenic composition according to any one of items 44-61,         wherein said immunogenic polypeptide or fusion polypeptide is         recombinantly produced.     -   63. Immunogenic composition according to any one of items 44-62,         further comprising an agent with adjuvant effect.     -   64. Immunogenic composition according to item 63, further         comprising an agent with adjuvant effect in an immuno-effective         amount.     -   65. Vaccine composition comprising an immunogenic composition         according to any one of items 44-64 and a pharmaceutically         acceptable carrier or excipient, such as a pharmaceutically         acceptable carrier or excipient selected from the group         consisting of a cream, emulsion, gel, liposome, nanoparticle, or         ointment.     -   66. Vaccine composition according to item 65, further comprising         an agent with adjuvant effect, such as an agent with adjuvant         effect in an immune-effective amount.     -   67. Vaccine composition according to any one of items 65-66 or         immunogenic composition according to item 63 or 64, wherein said         agent with adjuvant effect is selected from the group consisting         of Abisco/Matrix M, Matrix C and Matrix Q and silica.     -   68. Vaccine composition or immunogenic composition according to         item 67, wherein said agent with adjuvant effect is silica.     -   69. Vaccine composition according to any one of items 65-68,         which composition is formulated for intramuscular, intradermal,         subcutaneous or intranasal administration, such as for         intramuscular administration.     -   70. Vaccine composition according to any one of items 65-69,         which composition is capable of eliciting serum and/or mucosal         antibody responses in a mammalian subject, such as a porcine or         human subject, such as a porcine subject.     -   71. Vaccine composition according to item 70, wherein said         antibody response is in the form of IgG, IgA and/or IgM         antibodies in the serum and/or mucosa.     -   72. Vaccine composition according to any one of items 65-71, for         use in the prophylactic treatment of a mammalian subject         susceptible to Streptococcus suis infection, such as a human         subject or porcine subject, such as a porcine subject.     -   73. Method for the production of an antiserum comprising the         step of administering an immunogenic composition according to         any one of items 44-64, to a mammalian host to produce         antibodies in said host and recovering antiserum containing the         antibodies produced in the host.     -   74. Antiserum obtainable by the method defined item 73.     -   75. Method for prophylactic treatment of a Streptococcus suis         infection in a mammalian subject, comprising administering to         said mammalian subject in need thereof an immunologically         effective amount of an immunogenic composition as defined in any         one of items 44-64, of a vaccine composition as defined in any         one of items 65-72, or of an antiserum as defined in item 74.     -   76. Method for prophylactic treatment of a Streptococcus suis         infection in a mammalian subject, comprising administering to         said mammalian subject in need thereof an immunologically         effective amount of an immunogenic polypeptide as defined in any         one of items 1-12, a immunogenic polypeptide fragment as defined         in any one of items 13-16 or 34-39, or as fusion polypeptide as         defined in any one of items 17-39.     -   77. Method for prophylactic treatment according to item 75 or         76, wherein said mammalian subject is a porcine or human         subject, such as a porcine subject.     -   78. Method for prophylactic treatment according to any one of         items 75-77, comprising administering on one single occasion or         on multiple separate occasions.     -   79. Method for prophylactic treatment according to any one of         items 75-78, wherein said administration is to piglets, gilts or         sows.     -   80. Method for prophylactic treatment according to any one of         times 75-79, wherein said administration is intramuscular,         intradermal, subcutaneous or intranasal administration, such as         intramuscular administration.     -   81. Method for prophylactic treatment according to any one of         times 75-80, wherein, upon administration, serum and/or mucosal         antibody response is elicited in said mammalian subject.     -   82. Method for prophylactic treatment according to item 81         wherein said antibody response is in the form of IgG, IgA and/or         IgM antibodies in the serum and/or mucosa.     -   83. Antibody or fragment thereof, which is specific for an         immunogenic polypeptide as defined in any one of items 1-12, an         immunogenic polypeptide fragment as defined in any one of items         13-16 and 24-39 or a fusion polypeptide as defined in any one of         items 17-39, which antibody or fragment thereof is polyclonal or         monoclonal.     -   84. An antibody preparation comprising one antibody or several         antibodies or fragments thereof according to item 83.     -   85. Method for prophylactic treatment of a Streptococcus suis         infection in a mammalian subject, comprising passive         immunization by administering to said mammalian subject in need         thereof an antibody preparation according to item 84.     -   86. Immunogenic composition according to any one of items 44-64         for the use in the prophylactic treatment of a mammalian subject         susceptible to Streptococcus suis infection, such as a human         subject or porcine subject, such as a porcine subject.     -   87. Use of an immunogenic peptide as defined in any one of items         1-12, a immunogenic peptide fragment as defined in to any one of         items 13-16 or 34-39 or a fusion polypeptide as defined in any         one of items 34-39, for the manufacture of a medicament for use         in the prophylactic treatment of a mammalian subject susceptible         to Streptococcus suis infection. 

The invention claimed is:
 1. A fusion polypeptide comprising a) a first immunogenic polypeptide unit, and b) a second immunogenic polypeptide unit, wherein said first and second immunogenic polypeptide units are immunogenic polypeptide fragments selected from the group consisting of amino acid sequences of at least 100 amino acids in length with at least 80% identity to fragments of SEQ ID NO:4, amino acid sequences of at least 100 amino acids in length with at least 80% identity to fragments of SEQ ID NO:3, amino acid sequences of at least 100 amino acids in length with at least 80% identity to fragments of SEQ ID NO:2, an amino acid sequence with at least 80% identity to a fragment comprising SEQ ID NO:5, provided the fragment comprising the amino acid sequences with at least 80% identity to SEQ ID NO:5 is 100-500 amino acids long; and an amino acid sequence with at least 80% identity to a fragment comprising SEQ ID NO:6, provided the fragment comprising the amino acid sequences with at least 80% identity to SEQ ID NO:6 is 100-500 amino acids long.
 2. The fusion polypeptide according to claim 1, wherein the first and second immunogenic polypeptide units comprise an amino acid sequence that is at least 80% identical to the contiguous amino acid sequence of SEQ ID NOS: 38, 7, 8, 9, 10, 11 or
 12. 3. The fusion polypeptide according to claim 1, wherein the first and second immunogenic polypeptide units comprise an amino acid sequence that is at least 80% identical to the contiguous amino acid sequence of SEQ ID NOS: 7, 8, 9, 10, 11 or
 12. 4. The fusion polypeptide according to claim 1, wherein said fragments are 100-500 amino acids long.
 5. The fusion polypeptide according to claim 2, wherein said fusion polypeptide comprises an amino acid sequence selected from the group consisting of SEQ ID NO:92, SEQ ID NO:93, SEQ ID NO:94, SEQ ID NO:95, SEQ ID NO:96, SEQ ID NO:34, and SEQ ID NO:35.
 6. The fusion polypeptide according to claim 1, further comprising a third immunogenic polypeptide unit, wherein said third immunogenic polypeptide unit is from a different native protein than said first and second immunogenic polypeptide units.
 7. The fusion polypeptide according to claim 6, comprising an immunogenic polypeptide unit with at least 80% identity with SEQ ID NO:8, an immunogenic polypeptide unit with at least 80% identity with SEQ ID NO:10 and an immunogenic polypeptide unit with at least 80% identity with SEQ ID NO:12.
 8. The fusion polypeptide according to claim 7, comprising SEQ ID NO:107 or SEQ ID NO:108 or an amino acid sequence which exhibits at least 80% identity to SEQ ID NO:107 or an amino acid sequence which exhibits at least 80% identity to SEQ ID NO:108.
 9. The fusion polypeptide according to claim 6, wherein said fusion polypeptide comprises an amino acid sequence selected from the group consisting of amino acid sequences which exhibit at least 80% identity to SEQ ID NO:107, amino acid sequences which exhibit at least 80% identity to SEQ ID NO:108, amino acid sequences which exhibit at least 80% identity to SEQ ID NO:109, and amino acid sequences which exhibit at least 80% identity to SEQ ID NO:110.
 10. The fusion polypeptide according to claim 1, wherein said first and second immunogenic polypeptide units are immunogenic polypeptide fragments selected from the group consisting of amino acid sequences of at least 100 amino acids in length with at least 95% identity to fragments of SEQ ID NO:4, amino acid sequences of at least 100 amino acids in length with at least 95% identity to fragments of SEQ ID NO:3, amino acid sequences of at least 100 amino acids in length with at least 95% identity to fragments of SEQ ID NO:2, a fragment comprising an amino acid sequence with at least 95% identity to SEQ ID NO:5, provided the fragment comprising the amino acid sequences with at least 95% identity to SEQ ID NO:5 is 100-500 amino acids long; and a fragment comprising an amino acid sequences with at least 95% identity to SEQ ID NO:6, provided the fragment comprising the amino acid sequences with at least 95% identity to SEQ ID NO:6 is 100-500 amino acids long.
 11. An immunogenic polypeptide, comprising an amino acid sequence selected from i) an amino acid sequence selected from the group consisting of SEQ ID NO: 7, SEQ ID NO:8, SEQ ID NO:9, SEQ ID NO:10; and ii) an amino acid sequence with at least 80% identity to an amino acid sequence defined in i), wherein the amino acid sequence selected from (i) and (ii) is 100-500 amino acids long, and wherein said immunogenic polypeptide further comprises terminal, a tag selected from the group consisting of a His-tag, a myc tag, a SL-tag according to SEQ ID NO:32, a LSL-tag according to SEQ ID NO:33, an amino acid sequence with a least 80% identity to SEQ ID NO:32, and a FLAG tag, and/or methionine-threonine at the N-terminus.
 12. An immunogenic polypeptide, comprising an amino acid sequence selected from i) an amino acid sequence of at least 100 amino acids length selected from the group consisting of, SEQ ID NO:7, SEQ ID NO:8, SEQ ID NO:9, SEQ ID NO:10; and ii) an amino acid sequence of at least 100 amino acids length with at least 85% identity to an amino acid sequence defined in i), wherein said immunogenic polypeptide further comprises, a tag selected from the group consisting of a His-tag, a myc tag, a SL-tag according to SEQ ID NO:32, a LSL-tag according to SEQ ID NO:33, an amino acid sequence with a least 80% identity to SEQ ID NO:32, and a FLAG tag, and/or methionine-threonine at the N-terminus.
 13. An isolated immunogenic composition comprising at least one immunogenic polypeptide according to claim
 11. 14. A vaccine composition comprising an immunogenic composition according to claim 13 and a pharmaceutically acceptable carrier or excipient.
 15. An isolated immunogenic composition according to claim 13, further comprising an agent with adjuvant effect, which composition is capable of eliciting serum and/or mucosal antibody responses in a mammalian subject.
 16. An isolated immunogenic composition according to claim 15, which composition is formulated for intramuscular, intradermal, subcutaneous or intranasal administration.
 17. A method comprising administering a vaccine composition according to claim 14 to a mammalian subject susceptible to Streptococcus suis infection.
 18. The fusion polypeptide according to claim 1, wherein said first and second immunogenic polypeptide units are immunogenic polypeptide fragments selected from the group consisting of fragments of SEQ ID NO:4 of at least 100 amino acids in length, fragments of SEQ ID NO:3 of at least 100 amino acids in length, fragments of SEQ ID NO:2 of at least 100 amino acids in length, a fragment comprising SEQ ID NO:5, provided the fragment is 100-500 amino acids long; and a fragment comprising SEQ ID NO:6, provided the fragment is 100-500 amino acids long.
 19. The fusion polypeptide according to claim 1, wherein said immunogenic polypeptide fragments are selected from the group consisting of SEQ ID NO:5; SEQ ID NO:38, SEQ ID NO:6, SEQ ID NO:7, SEQ ID NO:8, SEQ ID NO:9, SEQ ID NO:10, SEQ ID NO:11 and SEQ ID NO:12.
 20. The fusion polypeptide according to claim 1, wherein said immunogenic polypeptide fragments are selected from the group consisting of fragments SEQ ID NO: 7, SEQ ID NO:8, SEQ ID NO:9, SEQ ID NO:10, SEQ ID NO:11 and SEQ ID NO:12.
 21. An immunogenic composition comprising at least one fusion polypeptide according to claim
 1. 22. A vaccine composition comprising a fusion polypeptide according to claim 1 and a pharmaceutically acceptable carrier or excipient.
 23. An isolated immunogenic composition according to claim 21, further comprising an agent with adjuvant effect, which composition is capable of eliciting serum and/or mucosal antibody responses in a mammalian subject.
 24. An immunogenic composition according to claim 21, which composition is formulated for intramuscular, intradermal, subcutaneous or intranasal administration.
 25. A method comprising administering a vaccine composition according to claim 23, to a mammalian subject susceptible to Streptococcus suis infection. 